In a large soup pot over high heat, add one tablespoon of sesame oil and sear the beef on all sides until browned but not cooked through, about 3-5 minutes. Remove the beef from the pot. Add the remaining tablespoon of sesame oil and saute the onions until tender, about 5-10 minutes.
Add the garlic and saute until fragrant, about 1-2 minutes. Then add the sliced cherry tomatoes and saute until they start to release their moisture, about 2-3 minutes more.
Deglaze the pot by adding the mirin and rice vinegar. Stir and scrape up any browned bits, then pour in the soy sauce. Stir to combine.
Prepare the broth by stirring the beef and garlic bases into the quart of water. Pour the broth into the pot and bring to a simmer. Continue to simmer for about 5-10 minutes.
While the broth simmers, fry each egg in one tablespoon of butter until the yolk reaches your desired doneness. For a wobbly center, fry for 3-5 minutes, for a hard center, fry for 6-8 minutes.
Stir the sriracha into the broth, as desired. Then add the broccoli florets. If frozen, let the ramen come back up to a simmer. If fresh, let the florets simmer for about 3 minutes, until they are bright green. Return the beef to the pot and stir to combine.
Then add the uncooked udon or ramen noodles to the pot. Cook for 2-3 minutes, until the noodles are cooked al dente. Use a ladle to spoon the ramen into serving bowls. Serve the fried egg on top with a squirt of sriracha or add on some kimchi for a spicy flair. Enjoy!