Cook the pasta according to the package instructions in a large pot of salted boiling water. Before draining, be sure to reserve about a cup of pasta cooking water.
In a large skillet or frying pan, melt the butter over medium heat.
When the butter starts to turn brown, add the sage leaves and cook until they become crispy. Remove from the pan and set aside.
Add the minced garlic and sauté for about 1 minute until fragrant.
Pour in the white wine and allow it to simmer for a couple of minutes, reducing by half.
Reduce the heat to low, and add the pureed pumpkin, tomato paste (puree), Parmesan cheese, and nutmeg to the skillet and stir well.
Add pasta water to the sauce, a little at a time until the sauce reaches the desired consistency.
Stir the cooked pasta into the sauce, adding a little more pasta water if needed.
Serve immediately topped with crispy sage leaves.