Heat the oven to 350°F and lightly grease a 9x13-inch baking dish.

Without separating the rolls, slice the entire sheet in half horizontally with a long serrated knife, so you have a top slab and a bottom slab.

Set the bottom slab cut-side up in the baking dish.

Layer the ham evenly over the rolls, then lay the Swiss cheese slices on top so every roll gets some.

Set the top slab of rolls back on, cut-side down.

Whisk the melted butter and Dijon mustard together in a small bowl until smooth.

Brush the butter mixture generously over the tops of the rolls, letting it soak into the seams.

Cover the dish tightly with foil and bake for 15 minutes, until the cheese has fully melted (check by lifting a corner roll).

Uncover and bake for another 5 minutes, until the tops are golden and slightly crisp.

Let the sliders rest for 5 minutes, then cut along the roll lines into individual sliders and serve warm.