Twice Baked Potato Casserole

Name: Twice Baked Potato Casserole
Ingredients: Nonstick cooking spray; 2.5 pounds (1.15 kilograms) baking potatoes, such as russets; 4 cloves garlic, peeled; Kosher salt and freshly ground black pepper; 1/2 cup (125 milliliters) buttermilk or heavy cream; 1/2 cup (125 milliliters) cream cheese; 1/2 cup (125 milliliters) sour cream; 3 tablespoons unsalted butter; 8 slices bacon, cooked crisp, rendering reserved; 5 green onions; 1 1/2 cups (170 grams) grated Cheddar; 2 tablespoons olive oil or reserved bacon fat