Preheat oven to 350 degrees F.

Cook the pasta to package directions in salted water, make sure the noodles are al dente. Drain and set aside.

Make the cheese sauce:

While pasta is cooking, prepare the cheese sauce. Melt 4 tablespoons of butter in a large saucepan or dutch oven over medium heat.

Add the flour and whisk to combine. Add the cayenne pepper and cook over medium-low heat for about 3-4 minutes, whisking, until the flour mixture becomes light brown in color.

Add the milk while whisking and cook over medium heat for about 5 minutes or until the sauce thickens, whisking often.

Lower the heat to and cook for about 10 minutes, whisking occasionally.

Make the breadcrumb topping:

While cheese sauce is cooking, prepare the breadcrumb topping. Melt 2 tablespoons of butter in a small fry pan over medium high heat.

Add the garlic and cook for 30 seconds or until fragrant.

Add the breadcrumbs and raise the heat to high and toast for about 1 minute before stirring. Continue until the bread crumbs become toasty.

Stir in the lemon zest and season with kosher salt and remove from heat to cool.

Assemble the mac and cheese:

Once the sauce has thickened, remove from heat and stir in the mascarpone until melted. Add the fontina and cheddar cheese and stir to melt. If the cheese isn't melting, turn the burner on low and heat until the cheese melts and becomes smooth with the sauce.

Add the drained pasta to the sauce and stir to combine, getting the cheese in all of the nooks and crannys of the pasta. Gently fold in the lobster meat.

Spoon the pasta into a 9x13-inch baking dish (or 6 to 8 2-cup gratin dishes). Sprinkle the bread crumb mixture on top of the pasta and bake for about 15-20 minutes or until the pasta is bubbly and lightly browned on top.