Heat 1 tablespoon olive oil in a small skillet. Add prosciutto and sauté until crispy. Set aside.
Heat remaining olive oil in a large skillet. Add shallots and sage; sauté until translucent. Add butternut squash and sauté for 3-5 minutes. Add broth. Simmer until the squash is tender. Discard sage sprig.
Process 1/3 of the sauce in a blender until smooth. Combine with the remaining sauce mixture.
Cook Farfalle according to package directions. Drain and toss pasta with sauce. Stir in the cheese and season with salt and pepper.
