Pierogi with Butternut Squash and Sage

A fun main course for autumn or winter. The pierogi dough is extremely easy to work with. Ingredients listed below: The butternut squash filling: A 3-lb (or slightly smaller) butternut squash 5 large or 10 small sage leaves Salt and pepper to taste For the pierogi dough: 2 cups all-purpose flour 3/4 cup sour cream 1 large egg 1/4 cup olive oil 1/2 teaspoon salt