1. Start by bringing a large pot of salted water to a boil. Cook the spaghetti according to package instructions until al dente. Reserve 1/2 cup of the pasta water and then drain the rest.
2. In a large pan, heat the olive oil over medium heat. Add the sliced garlic and sauté until it’s golden brown and fragrant, about 2 minutes. Be careful not to burn the garlic.
3. Add the sliced mushrooms to the pan and cook until they are tender and slightly browned, around 5-7 minutes. Season with salt, black pepper, and red pepper flakes.
4. Add the cooked spaghetti to the pan, along with the reserved pasta water. Toss everything together until the pasta is well-coated with the garlicky oil and mushrooms.
5. Remove from heat and stir in the fresh parsley. If using, sprinkle the grated Parmesan cheese over the top and gently toss to combine.
6. Serve immediately, with extra Parmesan on the side for those who want a little more cheesy goodness.

One of my favorite tips is to always reserve some pasta water. It creates a silky sauce that binds the flavors together beautifully.