In a large stock pot, bring salted water to a boil. Once boiling, add pasta and cook to just al dente.
Preheat oven to 350 degrees
While pasta cooks, melt 6 tablespoons of butter in a skillet.
Add flour to butter and stir over medium heat for about 1 to 2 minutes, until slightly browned.
Add the milk and whisk to remove any lumps. Add the salt and pepper.
Cook mixture for 5-6 minutes over medium-high heat until sauce thickens and begins bubbling.
While sauce cooks, in a small skillet melt remaining 1 tablespoon of butter. Saute onions and garlic until soft and fragrant.
Add lobster meat to onions and garlic to combine flavors and cook for 2-3 minutes. Too long and you will have tough meat!
Once sauce has thickened, mix in cheese, reserving about 1/2 cup of each cheese for topping. Whisk until melted and smooth. Remove from heat.
Combine sauce, drained pasta and lobster meat together and mix until coated.
Move pasta into a greased 9x13 baking dish and top with remaining cheese.
Bake at 350 degrees for 20-25 minutes.
Place under broiler for 2 minutes to make a golden top. Watch closely!