In a medium bowl, mix together pumpkin puree, ricotta, Parmesan, egg yolk, nutmeg, salt, and pepper until well combined. This is your filling!
Lay out wonton wrappers on a clean surface. Place about 1 teaspoon of filling in the center of each wrapper.
Dip your finger in water and run it along the edges of each wrapper. Fold over to create a triangle, pressing firmly to seal and removing any air bubbles. Make sure they're sealed tight or they'll open during cooking!
Bring a large pot of salted water to a gentle boil. Working in batches, cook ravioli for 3-4 minutes until they float to the top. Use a slotted spoon to carefully remove them.
While ravioli cook, make the sauce: In a large skillet over medium heat, melt butter. Add sage leaves and cook until butter begins to brown slightly and sage gets crispy, about 3-4 minutes. Add garlic and cook for 30 seconds more.
Add cooked ravioli to the butter sauce and gently toss to coat. Serve immediately with extra Parmesan, crispy sage leaves, and pine nuts if using. So good!