Place squash into a large pot. Pour chicken stock into pot until squash is covered. Cover pot and bring stock to a boil. Allow squash to simmer until soft. Drain and add squash into a mixing bowl; allow to cool to room temperature.

Mash squash with a potato masher or blend it in a food processor until smooth. Add mascarpone and ricotta and mix with squash until incorporated. Season with salt, pepper and nutmeg. If you like sage you can chop a few fresh leaves and add it to the mixture.

Using a cookie sheet topped with wax paper, spread out several discs of wonton dough and place 1 tablespoon of filling in center of each sheet of dough.

Wet your fingers and moisten the edges of the dough. Place another disc of dough on top of the ones with the filling and seal edges making sure there is no air between the filling and the dough. Use the prongs of a fork to press around the edges to further seal.

Continue with this process until all discs have been filled and sealed. Meanwhile bring a medium sized pot of salted water to boil.

Drop 3-4 ravioli into the boiling water at a time. You will need to do this in batches to make sure the water continues to boil and the ravioli don’t stick together.

Allow ravioli to cook for about 2-3 minutes until dough is cooked and pasta begins to float. Use a slotted spoon to remove the ravioli from the water and place them on a plate and tent with foil to keep warm. Continue until all ravioli are cooked.

For the brown butter sauce:
Place one stick of butter in a medium sized saucepan and turn burner on to medium heat. Allow butter to melt. Swirl melted butter around in the pan continuously (the butter may foam up a bit at this point). Keep swirling until you see little brown bits at the bottom of the pan and the butter smells like caramel.

Turn off the heat and immediately pour the browned butter over the ravioli and serve.