In a large skillet heat oil and cook beef and pork, stirring occasionally, until browned, about 5 to 6 minutes. Add the onions, bell peppers, celery, salt, Essence, cayenne, and black pepper. Cook, stirring often, until the vegetables are wilted, about 10 to 12 minutes. Add the garlic and cook for 2 to 3 minutes.
Dissolve the flour in the water and add to the meat mixture. Stir until the mixture thickens slightly, about 3 minutes. Remove from the heat and add the green onions. Mix well and let cool.
In a mixing bowl, sift together flour, salt, and baking powder. Cut in the lard until mixture resembles coarse meal. In a small bowl, beat the egg with the milk. Gradually add the egg mixture to the flour mixture, working it to make a thick dough. Divide the dough into 12 equal portions and roll each portion of dough into a thin round about 5 inches in diameter. Place about 1/4 cup of meat filling in the center of each round and brush edges lightly with egg wash. Fold edges together and crimp closed with a fork.
Heat shortening in a deep pot or electric deep-fryer to 360 degrees F. Fry the pies, in batches, until golden brown. Drain on paper towels and serve immediately.
Combine all ingredients thoroughly and store in an airtight jar or container.
Recipe from "New New Orleans Cooking", by Emeril Lagasse and Jessie Tirsch. Published by William and Morrow, 1993.