01 - Preheat oven to 400°F. Toss squash cubes with olive oil, salt, and pepper. Spread on a baking sheet and roast until caramelized and tender, 25 to 30 minutes. Allow to cool slightly.
02 - On a clean surface, mound flour and create a well in the center. Add eggs and salt. Gradually incorporate flour into eggs with a fork, then knead for 8 to 10 minutes until dough is smooth. Wrap in plastic wrap and rest at room temperature for 30 minutes.
03 - Mash roasted squash until smooth. Stir in ricotta, Parmesan, nutmeg, salt, and black pepper until fully combined and creamy. Set aside.
04 - Roll dough on a floured surface into thin sheets about 1/16 inch thick. Place 1 teaspoon mounds of filling 1.5 inches apart on one sheet. Brush surrounding dough with water, cover with a second sheet, and press to seal. Cut into ravioli shapes. Arrange on floured surface and cover with towel.
05 - Melt butter in a skillet over medium heat. Add sage leaves and cook until butter turns golden brown and leaves crisp, about 3 to 4 minutes. Remove from heat.
06 - Boil salted water in a large pot. Cook ravioli in batches until they float, about 2 to 3 minutes. Remove with slotted spoon and transfer directly to sage butter. Gently toss to coat evenly.
07 - Plate ravioli warm with extra grated Parmesan and freshly ground black pepper.