Bring a pot of salted water to a boil. Add 200 grams of spaghetti and cook until cooked through (5-10 minutes). Drain and set aside. Reserve 2 tbsp of pasta water.
While the spaghetti is cooking, cut 1 shallot, 4 cloves of garlic, 4 shiitake mushrooms, 20 cherry tomatoes, and 2 tbsp of cilantro. Set aside.
Once the pasta is done, add 1 tbsp of olive oil to a large fry pan. Add the shallot and garlic. Cook for 30 seconds until shiny.
Next, add the shiitake mushrooms and cherry tomatoes. Cook for 2-3 minutes until the mushrooms are cooked through.
Add 1/4 cup of tom yum paste and cook for 15 seconds until fragrant.
Finally, add in 25 oz of marinara sauce and 2 tsp of fish sauce. Mix and bring to simmer.
Add the pasta and pasta water to the pan and mix. Remove from the heat.
Serve with 2 tbsp of cilantro and 1 tbsp of parmigiano reggiano as garnishes.