Cook the spaghetti according to package directions. Drain the spaghetti reserving ¼ cup of the pasta water.
Add the spinach, basil, garlic, shallot, walnuts, queso fresco, ⅛ tsp salt, and ⅛ tsp pepper to a food processor or blender and blend into a sauce.
Transfer the sauce into a large mixing bowl and stir in the olive oil. Season sauce with additional salt & pepper if needed.
Add the cooked spaghetti to the bowl and toss with the sauce until all the pasta is coated. Stir in a little bit of the reserved pasta water if needed to reach desired consistency.
