Stir pumpkin, ricotta, Parmesan, 1 tsp salt, pepper, and nutmeg in a bowl until smooth.
Line a sheet pan with parchment. Set out wrappers and a small bowl of water.
Spoon a heaping 2 teaspoons filling onto half the wrappers.
Brush edges with water, top with another wrapper, press out air, and seal firmly.
Crimp edges with a fork and arrange ravioli on the prepared pan.
Bring a large pot of water to a boil and season with 1 tbsp kosher salt.
Melt butter in a skillet over medium heat until golden and nutty, 3–4 minutes.
Stir in sage and garlic; cook 30 seconds. Off heat, add lemon juice and red pepper.
Boil ravioli in batches until they float and edges turn tender, 3–4 minutes.
Transfer ravioli to the skillet and gently toss with the butter sauce.
Plate and shower with extra Parmesan. Serve immediately.