Make the garlic purée and set aside.
Caramelize the white onions (sliced thinly) in 2 tablespoons vegetable oil over low heat until they reach a deep golden brown color. Set aside 1/2 cup for the meat mix and 1/2 cup for the demi glace you’ll make later (see recipe).
Next, in a small sauté pan combine ketchup and coke, whisking together over low heat. Reduce this mixture by half, remove from heat and allow to cool.
In a large sauté pan, add 2 tablespoons vegetable oil and allow to warm over low heat. Add both types of mushrooms and a touch of salt and pepper to taste. Cook until the mushrooms are soft, allow to cool, and then add mushroom mix to coke and ketchup mix.
In a large metal mixing bowl combine ground beef with mushroom coke/ketchup mixture, and all remaining ingredients — egg, bread crumbs, Romano and Cheddar cheese and 1/2 cup caramelized onions and the garlic purée.
Portion mixture into four equal football-shaped loaves. Bake on parchment-lined sheet pan for 15 minutes at 350 degrees.
Reduce temperature to 250 degrees for 30-45 minutes or until internal temperature reaches 155 degrees.
To assemble: Slice each of the four mini meatloaves in three pieces and serve over red bliss mashed potatoes. Top this with the demi glace.