Preheat oven to 350 degrees F. Spray a baking dish with nonstick spray.
Bring a large pot of salted water to a boil. Boil the pasta until al-dente. You want it to have a bit of bite because it will finish cooking in the oven. Drain well.
While the pasta boils add 3 tablespoons butter to a medium skillet and melt. Add the garlic and sauté 30 seconds then add in the lobster meat and sauté for 3-5 minutes. Add the parsley and cook another 30 seconds. Remove the lobster from the pan.
Add another 2 tablespoon of butter to the skillet. Throw in the crushed Ritz crackers and toss to coat. Toast the crumbs for 3-5 minutes, stirring frequently to avoid burning. Once the crumbs are lightly toasted, remove from the heat and set aside.
In the same pot you boiled the pasta, melt the remaining 4 tablespoons butter over medium heat. Whisk in the flour. Reduce the heat to medium-low and let cook and bubble for 1 minute, stirring once or twice to avoid burning. Gradually whisk in the milk and raise the heat up to medium-high. Bring the mixture to a boil, whisking frequently until the sauce has thickened, about 2-3 minutes. Remove from the heat and stir in all of the cheese, mustard powder, cayenne, salt and pepper. Stir until the cheese is fully melted. Stir in the pasta and about 3/4 of the lobster meat. Transfer to the prepared baking dish.
Evenly sprinkle on the remaining lobster chunks and then the toasted cracker crumbs. Place the baking dish on a baking sheet.
Bake for 20 minutes or until the crumbs are golden brown and the sauce is bubbling.
Remove from the oven and let sit five minutes (yeah, right). Dig in!!