Preheat your oven to 175°C (350°F). Slice the buns horizontally, keeping them attached on one side if possible, to create a top and bottom layer.
Spread a thin layer of Dijon mustard on the cut sides of the buns to add a tangy flavor that complements the savory fillings.
Lay slices of ham evenly across the bottom half of the buns, covering all the way to the edges for maximum flavor in every bite.
Place slices of cheese on top of the ham, ensuring they cover the filling generously so that they melt into a gooey layer during baking.
Close the buns and gently press down to pack the fillings slightly, which helps everything stay together during baking.
Melt the butter in a small bowl, then brush it generously over the top of the buns using a pastry brush, ensuring even coverage for a golden, crispy finish.
If desired, sprinkle sesame or poppy seeds on top of the buttered buns for added texture and visual appeal.
Place the assembled sliders on a baking sheet lined with parchment paper, cut side up, and bake in the preheated oven for 15–20 minutes, until the tops are golden brown and the cheese is bubbly.
Once baked, remove from the oven and let rest for about 5 minutes. This helps the cheese set slightly and makes slicing easier without losing gooeyness.
Slice into individual sliders if desired, and serve warm to enjoy the crispy tops and melty interiors.