In a skillet, heat olive oil over medium heat and add sliced onions with brown sugar. Sauté until the onions are golden and sweetly caramelized, about 8 minutes.

In a mixing bowl, gently combine the ground beef with smoked paprika, garlic powder, cayenne pepper, salt, and black pepper. Shape into eight even patties.

Preheat a grill or skillet to medium-high heat. Cook the patties for 3 minutes on each side, adding a slice of cheddar cheese on top in the final minute.

Brush the cut sides of the slider buns with melted butter and toast them until golden brown, about 1-2 minutes.

Spread a layer of smoky BBQ sauce on the bottom buns. Top with cheesy beef patties, caramelized onions, crispy pickles, and finish with the top buns.