Begin by filling a large pot with water and placing it on the stove over high heat. Once the water reaches a rolling boil, add a generous amount of salt and the spaghetti. Cook until al dente, typically around 8–10 minutes, stirring occasionally.

In a large skillet, heat 1 tablespoon of olive oil over medium-high heat. Add the sliced button and oyster mushrooms to the pan. Sauté for about 5–7 minutes until golden brown and slightly crisp, stirring occasionally.

Reduce the heat to low and pour in the remaining olive oil. Add the freshly chopped garlic to the pan with the sautéed mushrooms and cook for 1–2 minutes until fragrant and lightly golden.

Sprinkle in the chili flakes and pour in the reserved pasta water, around 1/2 cup. Season the sauce with salt to taste and allow it to simmer for about 2–3 minutes.

Add the drained spaghetti to the skillet, tossing gently with the mushroom sauce. Stir in freshly chopped parsley, then plate and garnish with grated Parmesan.