Place cooked pumpkin into a mixing bowl. Add salt, black pepper and cayenne pepper. Stir in mascarpone cheese, egg yolk and 1/3 cup Parmesan cheese, mixing until the filling is smoothly combined.
Place a wonton wrapper onto a working surface. Wet the tip of a finger in water then run it all along the outer edge of the wonton pastry to moisten. Place about 1 teaspoon of filling in the centre of the wonton. Fold the wonton in half to make a half-moon shape then press the edges to seal. Repeat with the remaining wonton wrappers.
Place a deep frying pan over medium-low heat. Stir in butter and unpeeled clove of garlic. Meanwhile, bring a saucepan of lightly salted water to a boil.
Drop the filled ravioli into the boiling water a few at a time then cook until they float to the top, about 2 minutes. Drain the ravioli then transfer them to the frying pan. Turn the heat up to medium-high then cook just until the ravioli are infused with garlic flavor, about 2 or 3 more minutes. Sprinkle with chopped sage, more black pepper and extra Parmesan cheese to taste.