Roasted Garlic Macaroni and Cheese

• 1 head garlic
• 1 tablespoon olive oil
• 12-16 ounces penne rigate
• 3 tablespoons unsalted butter
• 3 tablespoons all-purpose flour
• 2 cups milk
• 8 ounces white cheddar cheese, shredded
• 1 container (usually 5 to 6 ounces) Boursin (garlic and herb spreadable cheese)
• Salt and pepper