In a large skillet over medium heat, add the ground beef, chopped onion, and green bell pepper. Cook until the beef is browned and the vegetables are tender, about 7-10 minutes. Drain any excess fat.
Season the meat mixture with salt and pepper. Reduce heat to low and sprinkle the shredded cheddar cheese on top. Allow it to melt for about 2-3 minutes while stirring gently to combine.
In a small bowl, mix together the mayonnaise, Dijon mustard, and ketchup to create a creamy sauce. Set aside.
Preheat the oven to 350°F (175°C). Arrange the slider buns on a baking sheet, cut them in half if they aren't already.
Spoon a generous amount of the chopped cheese mixture onto the bottom half of each slider bun.
Drizzle the creamy sauce over the meat mixture and top with pickles. Place the top half of the bun on each slider.
Bake in the preheated oven for 10-12 minutes, or until the buns are slightly toasted and the cheese is bubbly.
Remove from the oven and garnish with chopped parsley for a fresh touch.
Notes
Arrange the sliders on a large platter and serve with a side of extra pickles and the creamy sauce for dipping.