Start by bringing a large pot of salted water to a rolling boil over high heat. Add 8 ounces of tagliatelle pasta, stirring gently. Cook according to package instructions, typically about 8-10 minutes, until al dente. Drain and reserve a cup of pasta water.

Heat 2 tablespoons of olive oil in a large skillet over medium heat. Add minced garlic and diced onion, sautéing until fragrant and translucent. Add 8 ounces of sliced baby Bella mushrooms and 1 diced zucchini. Stir occasionally and cook for another 3-4 minutes until the mushrooms soften and zucchini turns vibrant green.

Sprinkle in a pinch of red pepper flakes, along with salt and black pepper to taste, stirring well. Cook for an additional minute to allow the spices to infuse the vegetables with flavor.

Lower the heat and add ½ cup of pesto sauce to the skillet. Toss in drained pasta and mix gently to ensure all ingredients are coated evenly. Add reserved pasta water if needed to achieve a silky sauce.

Remove the skillet from heat and stir in freshly chopped parsley. Dish out into bowls and garnish with grated Parmesan cheese if desired. Enjoy warm!