Heat oven to 350 degrees F. Coat a 13″ x 9″ baking dish with nonstick cooking spray.

Bring a large pot of water to a boil. Cook pasta according to package directions, and then drain.

Meanwhile, in a medium-sized saucepan, cook bacon over medium heat until crisp. Transfer to paper towels. Carefully pour off drippings, reserving 2 tablespoons in the pan. Add butter.

Whisk flour into bacon grease until smooth. While whisking, slowly stream milk into flour mixture; whisk to remove any lumps. Stir in onion powder, salt,and pepper. Bring to a boil over medium-high heat,then reduce heat and simmer 2 minutes. In a large bowl, toss together cheddar, jack, and Farmer’s cheese.

Remove milk mixture from heat; whisk in American cheese and 1 1/4 cups of the cheddar mixture. Toss bacon pieces with remaining shredded cheese.

In pasta pot, combine cooked pasta and cheese sauce. Pour half into prepared dish. Sprinkle with half the bacon-cheese mixture. Repeat layering.

Bake for 20 minutes. Increase oven temperature to broil and broil for 3 minutes, until the top is browned. Cool slightly before serving.