Butternut Squash Mac and Cheese

INGREDIENTS

• 2 tablespoons butter
• 3 tablespoons all-purpose flour
• Salt
• 1 cup cream or half-and-half
• 2 cups (8 ounces) sharp Cheddar, grated
• 2 cups chicken stock
• 2 tablespoons chopped fresh thyme leaves, plus a few sprigs for garnish
• 1/2 cup grated Parmigiano-Reggiano, a couple of handfuls
• 1/4 teaspoon ground nutmeg, eyeball it
• 1 (10 ounce) box frozen cooked butter nut squash, defrosted
• Black pepper
• 1/2 medium onion
• 1 pound macaroni with lines, such as tubatini or mini penne rigate
• 1 tablespoon extra-virgin olive oil, 1 turn of the pan