Bring a large pot of salted water to a boil. Add pasta and cook, stirring, until al dente, 15-17 minutes. Reserve 1/2 cup pasta cooking water, then drain. Meanwhile, wash and dry all produce. Halve, peel, and thinly slice shallot. Roughly chop sage leaves until you have 1 TBSP. Thinly slice mushrooms. Finely chop garlic

While pasta cooks, in a medium microwave-safe bowl, combine butternut squash and a splash of water. Cover with plastic wrap and poke a few holes in wrap. Microwave until tender, about 2 minutes. Drain if necessary.

Heat a large drizzle of olive oil in a large pan over medium-high heat (use a nonstick pan if you have one). Add butternut squash and 1/4 tsp sugar. Cook, stirring occasionally, until browned and slightly crispy, 2-3 minutes. Add shallot and chopped sage. Cook, stirring, until lightly browned, 1-2 minutes. Add a pinch of chili flakes; season with salt.

Add mushrooms to pan and cook, stirring occasionally, until lightly browned, about 3 minutes. Add garlic and cook until fragrant, about 1 minute. Season with salt and pepper.

Add pasta and 3 TBSP butter to pan; stir until butter has melted. Add reserved pasta cooking water and half the Parmesan; stir until thoroughly combined. Season with salt and pepper.

Divide pasta between bowls. Sprinkle with remaining Parmesan and chili flakes (to taste).