Gather your ingredients and tools: a cast-iron skillet, spatula, small knife, and baking sheet.
Divide the ground beef into four equal portions and gently form each into small, flat patties about 2 inches in diameter. Avoid overworking the meat to keep the sliders tender and juicy.
Preheat your skillet over medium-high heat until it’s hot and slightly shimmering. Add a tiny bit of oil if needed to prevent sticking.
Place the beef patties in the skillet, leaving space between each. Cook for about 2-3 minutes until the edges are deeply caramelized and browned.
Flip each patty carefully with the spatula and cook for another 2-3 minutes until the second side is browned and the juices run clear. Place a slice of cheese on each patty during the last 30 seconds to melt.
While the patties cook, slice the buns in half and toast them cut-side down in the skillet or in a preheated oven at 180°C (350°F) for 2-3 minutes until golden and crispy.
Mix mayonnaise and mustard in a small bowl to make a simple sauce. Spread this mixture on the bottom buns for a flavorful base.
As the cheese melts, assemble each slider by placing a beef patty on the bottom bun, then topping with pickles, thinly sliced red onions, and a dollop of sauce.
Cap each slider with the top bun, gently pressing down to secure the toppings. Serve immediately while the patties are juicy and the buns are crispy.
Enjoy these messy, flavorful mini sliders with extra napkins—the perfect crowd-pleaser for any occasion!
