Combine the seasoning mix ingredients in a small bowl and set aside.
Melt the butter in a 1 quart saucepan over medium heat. Add the onions, celery, bell peppers, green onions, garlic, Tabasco, Worcestershire and seasoning mix. Saute until mixture starts sticking excessively, about 6 minutes, stirring occasionally and scraping the pan bottom well. Stir in the milk and catsup. Continue cooking for about 2 minutes, stirring occasionally. Remove from heat and allow mixture to cool to room temperature.
Place the ground beef and pork in an ungreased 13 by 9 backing pan. Add the eggs, the cooked vegetable mixture (removing the bay leaves) and the bread crumbs. Mix by hand until thoroughly combined. In the center of the pan, shape the mixture into a loaf that is about 1 1/2 inches high, 6 inches wide and 12 inches long. Bake uncovered at 350 degrees for 25 minutes, then raise heat to 400 degrees and continue cooking until done, about 35 minutes longer. Serve immediately as is or with "Very Hot Cajun Sauce for Beef" (separate recipe).
Adapted from Chef Paul Prudhomme's "Louisiana Kitchen". (hot spice level reduced by us, but otherwise unchanged.)