6 TB butter, divided
1 cup onion, finely diced
1 tsp red pepper flakes
2 small garlic cloves, minced
3 TB flour
3 cups whole milk
3 cups sharp cheddar cheese, grated
1 cup Parmesean cheese, grated
4 oz. mascarpone or cream cheese
3/4 cup panko bread crumbs
1/2 cup fresh chopped parsley
1 lb. penne or macaroni pasta
Add onion and saute until tender, about 5 minutes. Add red pepper flakes and garlic, stir for 1 minute.
Stir in 2 tablespoons butter, allow to melt, and then add the flour and stir for 1 minute.
Gradually whisk in 3 cups of milk; simmer until thick enough to coat a spoon, stirring frequently, about 5-10 minutes. Remove from heat and whisk in 2 1/4 cups of cheddar and all of the Parmesan cheese and marscapone. Season with salt and pepper.
Preheat oven to 375 F.
Lighly butter a 13×9x2 inch glass baking dish or similarly sized gratin dish.
Cook pasta in large pot of boiling water until very al dente. Drain well.
Toss pasta and cheese sauce and season again with salt and pepper, if needed. Transfer mixture to prepared baking dish and top with remaining cheese and breadcrumbs.
Bake until hot and topping is golden brown, about 30 minutes. Let sit for 5 minutes before serving.
Sorry, the pictures were more of an "after thought" since I had guests arriving while making this (thanks for helping Ashley!). Check out the link below to the original recipe for MUCH better photos (and bacon)!!
Recipe from http://www.lottieanddoof.com/2009/04/mac-cheese-lottie-doof-style/