Chicken Spaghetti

Ingredients

• 12 ounces uncooked spaghetti, broken into 2-inch pieces
• 1/4 cup butter, cubed
• 1 medium onion, chopped
• 2 garlic cloves, minced
• 3 tablespoons all-purpose flour
• 2 cups 2% milk
• 3 cups cubed cooked chicken breast
• 1 can (10-3/4 ounces) condensed cream of mushroom soup, undiluted
• 1 jar (4 ounces) diced pimentos, drained
• 4 ounces cream cheese, cubed
• 1-1/2 cups shredded cheddar cheese, divided
• 1/2 teaspoon pepper