This Cheese Pumpkin Pasta Casserole with Spinach is a rich and creamy autumn-inspired dish that combines tender pasta shells with a luscious pumpkin and cheese sauce. Infused with garlic, fresh thyme, and a hint of spice from crushed red pepper flakes and nutmeg, it’s topped with a blend of Gruyère, Parmesan, and ricotta cheese, then baked to bubbly perfection. Perfect as a comforting vegetarian main course for fall or winter dinners.