Preheat oven to 375. Prepare a 9 x13 casserole dish with Pam.
Place the butter in a medium saucepan, melt over medium-low heat, and cook until foaming. Add the flour and stir well with a wooden spoon for 1 - 2 min. Slowly pour in the milk, whisking to incorporate.
Attach the bay leaf to the onion wedge using cloves. Drop the studded onion into the milk mixture with the clove/bayleaf side down. Cook, stirring occasionally, until the mixture thickens, about 15 min.
Meanwhile cook the pasta according to package directions, but don't salt the cooking water.
Remove the studded onion from the sauce and discard. Add the Swiss and cheddar cheeses. Stir to combine and heat the sauce until the cheese is just melted. Season with salt and cayenne.
In a large mixing bowl, combine the sauce, bacon and cooked macaroni; toss to coat. Combine the bread-crumbs and Parmesan in a small bowl.
Pour the pasta mixture into the prpared baking dish and top with the breadcrumbs and
|