Set a skillet over medium-high heat and let it warm for about 2 minutes until it’s hot and begins to shimmer slightly.
Place the slices of ham in the skillet in a single layer, pressing down slightly to ensure contact with the hot surface.
Cook the ham for 2-3 minutes on each side, until the edges turn golden brown and crispy, and you hear a gentle sizzling sound.
Brush the caramelized ham slices generously with BBQ sauce, coating all sides for a smoky, sticky glaze.
While the ham cooks, slice the buns in half horizontally and brush the cut sides with melted butter using a basting brush.
Once the ham is glazed and crispy, remove it from the skillet and set aside briefly.
Place the buttered buns cut side down on the hot skillet and toast for 1-2 minutes until they’re golden and slightly crispy.
Layer the crispy ham slices onto the bottom halves of the toasted buns, then top each with a slice of cheese and a few rings of red onion.
Cover each slider with the top bun, pressing down gently to help everything meld together.
Arrange the assembled sliders on a baking sheet and bake in a preheated oven at 180°C (350°F) for 8-10 minutes, until the cheese is melted and the buns are warm and toasted.
Remove from the oven, let rest for 2 minutes, then serve warm, optionally garnished with extra onions or BBQ sauce on the side.
