01 - Preheat oven to 350°F. Line a baking sheet with parchment paper.
02 - Slice the slider rolls in half horizontally. Arrange bottom halves on the prepared baking sheet.
03 - Spread a thin layer of stone ground mustard on each bottom half. Add a small amount of mayonnaise if using.
04 - Layer sliced corned beef evenly on each roll. Top with Swiss cheese slices and a spoonful of shredded cabbage or sauerkraut.
05 - Place the top halves of the rolls over the fillings.
06 - In a small bowl, mix melted butter with poppy seeds and garlic powder. Brush the tops of the slider rolls with the butter mixture.
07 - Cover the sliders loosely with foil and bake for 10 minutes.
08 - Remove foil and bake for an additional 3–5 minutes, until tops are golden and cheese is melted.
09 - Remove from oven, sprinkle with chopped chives if desired, and serve warm.