Place everything into your pot: the spaghetti, sliced onion, garlic, mushrooms, tomatoes, spinach, basil, salt, pepper and crushed red pepper flakes. Add in the olive oil and then add in 4 1/2 cups of water. Bring everything to a high boil and turn it down just slightly after the water starts boiling if you need to. Then, you are literally just mixing everything up together using tongs.

Let the pasta cook for about 8 to 9 minutes. All of the water should be absorbed and you should end up with a lovely pasta dish with amazingly great flavor! If you have a little liquid left, cook for 1 to 2 minutes longer on low heat. Turn off the heat and mix together. By the time you serve the pasta, all of the liquid should be gone. Season with more salt and pepper and serve immediately.