1. Heat 1 tablespoon oil over medium-low heat in a medium skillet. Add onions, season with salt, and cook slowly for 30-40 minutes, stirring occasionally, until onions are caramelized, golden, and soft. Raise heat to medium, add 1/4 cup of water to pan, and stir to scrap up any browned bits. Simmer until all water has evaporated. Remove onions to a small bowl and set aside.
2. Add remaining 1 tablespoon oil to skillet and add ground beef, mustard, and season generously with salt. Cook over medium heat, breaking up beef into bite-sized pieces, until meat is cooked-through, about 4-5 minutes. Use a slotted spoon to remove beef to a medium bowl.
3. Place a slice of American cheese on each tortilla. Melt cheese onto tortilla by either microwaving for about 10 seconds each or heating tortillas in a skillet over medium heat.
4. Top each melted cheese covered tortilla with beef, lettuce, tomato, bacon, animal spread, and caramelized onions.

Animal Spread

1. Combine mayonnaise, ketchup, sweet pickle relish, and white vinegar in a small mixing bowl. Season with Kosher salt.