Prepare pasta according to package directions and set aside (add a pat of butter or a tablespoon of olive oil to prevent sticking after pasta has been cooked)
In the meantime, heat butter over medium-high heat until melted and then add garlic and shallots.
Cook until fragrant, about 1 to 2 minutes, then add flour (and tomato paste if using) and whisk until a paste forms. Do not allow this to brown!
Add paprika, cayenne, salt, pepper, and bay leaf.
Slowly add milk and whisk to incorporate. Reduce heat to medium and continue cooking until mixture thickens, about 4 to 5 minutes.
Remove mixture from heat and then stir in shredded cheeses.
Taste sauce and add more salt/pepper if needed.
Add lobster meat to sauce and then combine with pasta.
Pour pasta into a greased 9 by 11 baking dish and top with breadcrumbs
Bake for about 30 to 35 minutes until top is lightly browned.
Casserole can be made ahead and reheated at 350 degrees until heated through (cover with foil when reheating to prevent the pasta from drying out)