Mac n Cheese

1 package (16 ounces) small pasta shells 1/2 cup butter, cubed 1/2 cup all-purpose flour 1/2 teaspoon onion powder 1/2 teaspoon ground chipotle pepper 1/2 teaspoon pepper 1/4 teaspoon salt 4 cups 2% milk 2 cups shredded sharp white cheddar cheese 2 cups shredded Manchego or additional white cheddar cheese

In a 6-qt. stockpot, cook pasta according to package directions. Drain; return to pot. Meanwhile, in a large saucepan, melt butter over medium heat. Stir in flour and seasonings until smooth; gradually whisk in milk. Bring to a boil, stirring constantly; cook and stir until thickened, 6-8 minutes. Remove from heat; stir in cheeses until melted. Add to pasta; toss to coat.