1 lb ground beef (80/20 lean-to-fat ratio preferred)
2 large yellow onions, thinly sliced
2 tablespoons unsalted butter
1 tablespoon olive oil
1 package (12 count) Hawaiian sweet rolls
6 slices Provolone or Swiss cheese
1 teaspoon Worcestershire sauce
1/2 teaspoon garlic powder
Salt and black pepper to taste
2 tablespoons melted butter (for the glaze)
1 teaspoon poppy seeds or sesame seeds
1/2 teaspoon dried parsley
Instructions
Heat the olive oil and 2 tablespoons of butter in a large skillet over medium-low heat. Add the sliced onions and a pinch of salt. Cook slowly, stirring occasionally, for about 20-25 minutes until the onions are deep golden brown and soft. If they start to stick, add a splash of water to the pan.
In a separate skillet over medium-high heat, brown the ground beef until fully cooked. Drain any excess grease. Stir in the Worcestershire sauce, garlic powder, salt, and pepper. Mix well and remove from heat.
Preheat your oven to 350°F (175°C). Without pulling the individual rolls apart, slice the entire slab of Hawaiian rolls in half horizontally. Place the bottom half in a baking dish lined with parchment paper or lightly greased.
Spread the cooked ground beef evenly over the bottom half of the rolls. Layer the caramelized onions over the beef, then top with the slices of cheese. Place the top half of the rolls back on top.
Whisk together the melted butter, poppy seeds, and dried parsley. Brush this mixture generously over the tops of the rolls. Cover the dish with foil and bake for 10 minutes. Remove the foil and bake for another 5-10 minutes until the cheese is melted and the tops are golden brown.