Preheat oven to 350 degrees.
Boil a large pot of salted water. Add the pasta and cook according to the directions on the package, until barely al dente, about 12 minutes, adjust depending on the pasta you use. Drain and pour into a +/-9x9 baking dish and set aside.
In the same large pot you used to boil the pasta, melt the butter over medium low heat. Add the flour and cook for 1-2 minutes, stirring constantly. Add the minced shallot and garlic sauté on low for 2-3 minutes until softened and fragrant.
Stir in the milk slowly, constantly whisking over medium low heat until milk is steaming, but not boiling. Remove milk from heat and add salt and pepper.
Small handful by handful, whisk the cheese into the milk, until you have roughly ¼ of the cheese remaining (you’ll add that to the top of the dish later). Continue whisking until cheese sauce is relatively smooth. Pour the cheese sauce over the pasta.
Pat shrimp very dry. Brush on both sides with barbeque sauce. Discard any remaining sauce that has touched the raw shrimp. Nestle shrimp into the top of the mac and cheese.
Top pasta with remaining cheese and panko crumbs. Place baking dish into the oven for 25-30 minutes, until cheese is bubbly, shrimp is cooked through and topping is lightly browned.
Remove from oven. Drizzle with bbq sauce. Top with freshly ground black pepper. Serve.