Instructions

• Preheat the oven to 350°F (175°C).
• Dice the 1 medium white onion into small pieces (about 1/4"–1/2").
• Heat 1 teaspoon oil in a medium saucepan or skillet over medium heat. Add the diced onion and sauté until fragrant and soft, about 3 minutes.
• Add 1/2 cup water and 1 teaspoon Worcestershire sauce to the pan with the onions. Bring to a boil, then reduce heat and simmer for 8 minutes. Remove from heat and set the onions and their juices aside.
• Place the 1 pound lean ground beef on a sheet of parchment paper. Flatten the beef with a rolling pin or your hands into an even rectangle about 1/4" thick.
• Evenly sprinkle 1/2 teaspoon salt and 1/2 teaspoon black pepper over the flattened beef.
• Using a sharp knife or pizza cutter, cut the beef rectangle into 12 equal patties.
• Use a metal straw or the handle of a wooden spoon to make several small vent holes in each patty (this helps them steam during baking).
• On a large baking sheet, spread the cooked onions and their juices evenly to form a thin layer across the sheet. Place the 12 patties on top of the onion layer.
• Cover the baking sheet with a second baking sheet turned upside down or with a large sheet of foil to trap steam. Bake in the preheated oven for 10 minutes.
• Carefully remove the cover (watch for steam). Immediately place one half of an American cheese slice on each hot patty so the cheese can soften.
• To assemble each slider: place a bottom slider bun, a spoonful of the cooked onions (from the baking sheet), a cheesed patty, 2 dill pickle chips, then the top bun. Serve warm.