½ teaspoon fresh thyme leaves, or ¼ teaspoon dried thyme, crushed between your fingers
1 teaspoon paprika
1 teaspoon chili powder
Preheat the oven to 375 degrees F. Cook the pasta in a large pot of rapidly boiling salted water until almost al dente, and drain.
In a large, heavy-bottom saucepan lightly sauté the onion over medium heat in the olive oil until it softens, 5 to 7 minutes. Stir in the garlic, cook for a few moments to mellow, and sprinkle in the flour. Cook for a minute or two until its raw flavor is gone. Remove from the heat, and add the bay leaf and milk all at once. Return to the heat and cook, stirring with a wooden spoon, for 5 to 10 minutes, or until the sauce thickens. If any floury lumps remain, whisk the sauce with a wire whisk for a few moments. Remove from heat and set aside.
Remove the bay leaf from the sauce. Combine the macaroni with eth sauce and mix in the diced bell pepper, mustard seeds, thyme, paprika, chili powder, prepared mustard, dry mustard, Cheddar cheese (Reserve ¼ cup for the topping), sliced olives, salt and pepper, and hot sauce. Pour into a large, shallow baking pan. Sprinkle the top with the reserved cheese, then with the crumbs, and dot with butter.
Bake for 30 minutes, or until the topping is golden, the cheese melty, and the crumbs crispy. Serve right away.