Heat oven to 450° F. Rub 1 tablespoon of the olive oil on red peppers and onion halves; place on a rimmed baking sheet. Cut off top quarter of the garlic and rub remaining 1 teaspoon olive oil on it; wrap garlic in aluminum foil and place on same baking sheet. Roast at 450° for 40 minutes, turning red peppers every 10 minutes. Place sausages on a separate baking sheet. During the last 10 minutes of cooking, place sausages in oven.
When cool enough to touch, remove stem, seeds and skin from peppers. Squeeze head of garlic to remove cloves. Place peppers, garlic cloves and onion in a blender with salt, pepper and cream. Blend until smooth. Slice sausages into coins; set aside.
Meanwhile, bring a pot of lightly salted water to boiling. Cook orecchiette 11 minutes or according to package directions. Drain and return to pot. Stir in sauce and sliced sausage. Garnish with parsley and cheese, if desired.