Creamy Purple Potato Soup with Skull Mushrooms aka Halloween “Witchyssoise”
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What’s Up, Hungry People
It’s October, which officially means it’s spooky season! I’m all about making freaky food for exactly 31 days out of the year. Craving a simple potato soup? Well now it’s SPOOKY potato soup, my guy.
This potato soup in particular has been brewing in my mind for a while, but we follow a strict soup season schedule. It’s kind of like the whole taboo about wearing white after Labor Day – except in this case, we can only eat soup from October to the end of March, when the soup tree is at its peak. (I’m kidding of course, we only follow this strict schedule for eating chili, as is the way).
I’d like to imagine this is the soup you’d be served after accidentally wandering into a witch’s den. Made with simple ingredients like purple potatoes, onions and button mushrooms – this witch has a few tricks up her sleeves.
“Vichyssoise?” More Like “Witchyssoise”
Based on a real life soup called a vichyssoise (pronounced vee-shee-SWAHZ; but sorta sounds like you’re saying “witchy-sauce” if you say it fast enough, hence the name of the recipe), this potato soup uses purple potatoes and red onions to get it’s unique hue. The potatoes and onions are roasted with whole cloves of garlic and button mushrooms carved to look like spooky little skulls. Once the veggies are roasted, everything gets blended in a big pot with an immersion blender (because nothing says “witch’s brew” like stirring a bubbling cauldron of soup, right?).
I did use a few drops of purple food coloring to help bring out the purple color even more, but the food coloring is totally optional. Without the food coloring, the soup is still pretty purple but leans a bit on the lighter side once the heavy cream and mozzarella have been added. While you could technically skip the cream and cheese to keep the natural purple colors intact, you won’t end up with the same flavor profile as a traditional vichyssoise, which is what we are aiming for here.
Vichyssoise is traditionally made with white potatoes, leek and cream. The same flavor profile can be obtained by combining purple potatoes, red onion and cream to a shockingly close degree. My soup uses a garlic broth bouillion base but chicken or vegetable broth can also be swapped in.
Making Skull Mushrooms
I’ve been obsessed with these awesome mushroom skulls for years but never could find an excuse to make them. Making the mushrooms into skulls is simple enough, but the most imporant part is using large enough mushrooms so you don’t lose any of the ghoulish features.
This tutorial walks you through how to make these mushroom skulls at home. In the tutortial, they use a straw and a knife to cut out the eyes and nose and make the mouth. I took a bit of a more rustic approach and used a strawberry corer to pluck out eye holes; a knife to cut small slits for the nostrils; and a lemon zester to make the lines that represent the teeth on the stem. No matter which way you carve them, you’ll end up with some pretty spooky looking mushrooms.
Here’s What You Need:
Rustle up your inner ghoul – tonight we’re stewing up a delicious storm.
- Purple potatoes – For the base of the soup, adding earthy flavor and that distinct spooky color.
- Red onion – Adds sweetness and a deep, rich hue that complements the potatoes.
- White button mushrooms – Sliced into little skulls for a spooky garnish.
- Garlic – Roasted whole with the veggies for a subtle, savory flavor.
- Purple carrots – Adds extra color and texture to the roasted veggies.
- Vegetable oil – For roasting, keeping everything golden and delicious.
- Sea salt & pepper – The basics for seasoning the veggies and the soup.
- Garlic broth – A flavorful base that pairs perfectly with the roasted garlic and potatoes.
- Heavy cream – Helps to create a smooth, velvety texture.
- Mozzarella cheese – Adds a bit of creaminess and a hint of cheesy goodness.
- Smoked salt – Gives a subtle, smoky flavor to the finished dish (optional, I smoked my own salt!)
- Italian seasoning – Balances out the flavors with herbs.
- Hatch green chile pepper flakes – For a little heat; swap with red pepper flakes if preferred.
- Microgreens – Adds color and texture as a garnish, making the soup look extra special.
- Mascarpone cheese – Piped on top to create a spooky message or design.
- Purple food coloring (optional) – To make the purple hue pop even more.
Let’s Cook
Preheat your oven to 400°F and start prepping the vegetables. Cut the potatoes into halves, slice the onion, peel the garlic (leaving the cloves whole), and slice your button mushrooms into skull shapes. If you’re using whole purple carrots, peel and chop them into even pieces. You can leave the baby carrots as they are, just make sure they’re all roughly the same size for even roasting.
Once prepped, spread all the veggies out on a greased baking sheet, making sure they’re in a single layer so they roast evenly. Drizzle everything with vegetable oil, give the pan a good shake to coat them, and season generously with salt and pepper. Pop them into the oven and roast for about 30 minutes or until they’re fork-tender.
Building the Broth
While your veggies are roasting, bring your garlic broth to a boil. If you’re using bouillon, just dissolve it in boiling water. Lower the heat to a gentle simmer while you wait for the roasted veggies.
Blending the Soup
When your veggies are done, pull out those adorable skull mushrooms and set them aside for the final garnish. Toss the rest of the roasted veggies into the simmering broth. Break out the immersion blender (seriously, it’s like casting a spell) and blend the veggies into the broth until it’s silky smooth. Keep stirring and scraping the bottom of the pot to make sure nothing’s sticking.
Finishing Touches
Once your soup is nice and smooth, stir in the shredded mozzarella and heavy cream. If you’re feeling extra spooky, this is the perfect time to add a few drops of purple food coloring to really bring out the color. Keep the soup simmering and season with smoked salt, Italian seasoning, and a pinch of those green chile flakes to taste.
Let it bubble away for about 15-20 minutes until it thickens up. While it’s simmering, get your mascarpone cheese ready by transferring it into a piping bag (or a plastic baggie with the corner snipped).
Serving the “Witchyssoise”
When you’re ready to serve, ladle the soup into shallow bowls. Garnish with microgreens and your skull mushrooms for that ultimate Halloween look. Use the mascarpone to pipe out an eerie message on top.
Surprisingly (or unsurprisingly, if you’re a long time reader) my husband ate a bowl of soup that literally was labeled “poisoned” without a second thought.
Tips for “Witchyssoise” Success
- Roasting is key: Make sure your veggies get that nice golden edge for maximum flavor.
- Don’t skip the immersion blender: Blending gives you the smooth texture that makes this soup shine.
- Adjust the spice level: If you’re not into heat, go easy on the chile flakes, or swap them for a milder option.
- Add food coloring gradually: If you’re using it, start with just a few drops and stir before adding more—too much, and you might end up with a soup that’s a little too intense.
- Keep your piping cool: If your mascarpone is too warm, it might not pipe well. Pop it in the fridge for a few minutes if needed.
Common Questions
- Can I use regular potatoes instead of purple potatoes? Absolutely! The soup will taste just as good, but it won’t have the spooky purple hue. You can still use the purple food coloring to achieve the same effect if you want.
- What if I don’t have an immersion blender? No worries! You can blend the soup in batches in a regular blender – just be careful with the hot liquid. Never overfill a blender with hot liquids, always blend at a quarter full and on the lowest setting possible to prevent explosions. Honestly, just get yourself an immersion blender, you won’t be sorry.
- Is the food coloring necessary? Nope, it’s totally optional. Without it, the soup will still have a purple tint, but it’ll be a bit more muted.
- Can I make this ahead of time? Yes! This soup reheats well, just store it in the fridge and heat it up when you’re ready to serve. If it sets thick, add a few tablespoons of water or broth to make it soup consistency again.
- How spicy is this with the chile flakes? It’s got a mild kick. If you’re sensitive to spice, you can leave them out or reduce the amount.
“Witchyssoise” brings a whole new level of spooky to your soup game, making it perfect for Halloween or whenever you’re feeling a little witchy (or just love a good pun, such as myself). The rich purple color, combined with those skull-shaped mushrooms, makes this dish stand out in the most fun way possible. The creamy base and roasted garlic add depth without overpowering the subtle sweetness of the purple potatoes. It’s easy to get lost in the process of whipping up this haunting dish – just don’t forget the ominous mascarpone lettering for that spooky final touch! Bring this to the table, and watch your guests be completely bewitched.
Witchy Vichyssoise
Equipment
- heavy bottom pot
- ladle
Ingredients
- 1.5 lb purple roasting potatoes sliced in halves
- ½ red onion sliced
- 5-6 white button mushrooms washed & sliced into skull shapes
- 8-10 purple baby carrots or 1-2 whole purple carrots, chopped
- 4-5 cloves garlic
- 2-3 tablespoons vegetable oil
- 1 teaspoon sea salt
- 1 teaspoon pepper
- 6 cups garlic broth made from garlic bouillion, can sub veg or chicken broth
- ½ cup heavy cream
- ½ cup mozzarella cheese shredded
- 1 teaspoon smoked salt + to taste
- 1 teaspoon Italian seasoning + more to taste
- ½ teaspoon hatch green chile pepper flakes + to taste, can sub red pepper flakes
- 1 cup microgreens Amaranth, pak choi, rambo radish, red veined sorrel, etc
- ½ cup mascarpone cheese in piping bag
- ¼ teaspoon purple food coloring gel
Instructions
- Preheat oven to 400°F. Prep the potatoes, onions, garlic, and mushrooms. Wash and slice the potatoes into even halves. Cut the onion into even slices. Peel the garlic but leave it whole. Trim the stems and slice the mushrooms in half, then use a straw or paring knife to cut eyes and nostrils; finally, use a zester or paring knife to create teeth on the stem. If using whole purple carrots, peel and chop into even-sized pieces (if using purple baby carrots, these can be left whole as long as they are all about the same size).
- Place all of the vegetables in a single layer on a greased baking sheet. Drizzle everything with the vegetable oil, shake the pan gently to coat the vegetables in oil, and season generously with salt and pepper. Roast in the oven for 30 minutes or until fork tender.
- Meanwhile, bring a pot of water to a boil and add the garlic bouillon – or if using prepared broth, bring the broth to a boil. Just prior to adding the vegetables, reduce the temperature to a low simmer.
- When the vegetables have finished roasting, remove the decorative skull mushrooms from the pan and set aside. Transfer the rest of the roasted vegetables immediately to the boiling broth. Use an immersion blender stick to blend the vegetables into a smooth soup while stirring occasionally to scrape up anything stuck to the bottom of the pot. Continue to blend with the immersion stick until all chunks are gone.
- Once smooth, add the shredded mozzarella and heavy cream. If using, add the purple food coloring to enhance the color. Bring the soup to a low bubble and stir constantly. Season with the smoked salt, Italian seasoning, and green chile flakes to your liking.
- Continue to simmer the soup for 15-20 minutes or until thickened. While the soup simmers, transfer the mascarpone cheese to a piping bag or plastic baggie with the tiniest bit of the corner snipped off.
- When ready to serve, ladle into shallow serving bowls and garnish the soup with microgreens and the roasted skull mushrooms. Use the mascarpone cheese to write an ominous message on top of the soup. Serve immediately and enjoy!
