Caramelize the onions

• Melt the butter in a skillet over medium heat, add the chopped onions and cook, stirring occasionally.
• Reduce the heat to medium-low, sprinkle in the sugar and cook, stirring occasionally, until soft and golden brown. If they stick or brown too quickly, lower the heat and add a splash of water.

Cook the beef

• Preheat the oven to 200 °C and grease a baking dish.
• In a skillet over medium-high heat, cook the ground beef, breaking it apart, until browned and fully cooked.
• Drain the excess grease and season with the burger seasoning and all-purpose seasoning.

Make the burger dressing

• Stir together the mayonnaise, ketchup, mustard and pickle juice in a small bowl until smooth.

Layer the sliders

• Slice the rolls in half horizontally and place the bottom half in the prepared dish.
• Layer with half of the cheese, the ground beef, caramelized onions and burger dressing.
• Top with the remaining cheese and cover with the top half of the rolls.

Brush and bake

• Brush the tops with the melted butter and sprinkle with sesame seeds.
• Bake uncovered until the cheese is melted and the tops are golden. Check after 10 minutes and loosely tent with foil if the rolls brown too quickly.

Slice and serve

• Slice into individual sliders and serve warm, with extra burger dressing on the side.