1. In a medium-size saucepan, combine butternut squash, salt, garlic and enough water to cover. Bring to boil; cook 8 minutes, or until squash is tender. Drain and transfer to a food processor.
2. Add sugar, egg yolk, sage, nutmeg and pepper. Pulse until smooth. Refrigerate until ready to use (up to one day ahead).Pasta:
3. On a work surface, blend together both flours. Make a well in the center and add eggs, water, oil and salt. Gently whisk together with a fork. Continue whisking, in a circular motion, slowly incorporating more and more flour. Continue until a soft dough is formed. With lightly floured hands, knead dough about 5 minutes.
4. Divide dough into six pieces. Working with one piece, keep remaining pieces covered with a clean cloth. With pasta machine set on its widest setting, pass dough through machine, then lightly dust with flour and fold in thirds. Repeat once. Continue to pass through machine, decreasing setting one notch each pass, stopping one notch before thinnest setting. Divide pasta sheet in half crosswise for easier handling.
5. Remove filling from refrigerator. Using a 1-1/2- to 2-inch ravioli cutter, mark circles on one sheet of pasta. Dollop a scant teaspoon filling in center of each circle. Top with a second sheet of pasta, and press to seal. Using cutter, press down firmly to cut out ravioli. Transfer to a sheet pan and dust liberally with semolina flour. Repeat with remaining dough and filling. (Ravioli can be frozen in a single layer. Add 1 minute to cook time.)sauce:
6. In saucepan, bring cream and Parmesan to simmering. Cook until thickened, about 5 minutes, then whisk in butter. Bring a large pot of lightly salted water to boiling; add ravioli. Once they begin to float, cook for 4 to 5 minutes. Drain and toss with sauce and sage.