Directions:
Step 1: Prep the Oven & Pan: Preheat your oven to 350°F. Lightly grease a 9×13-inch baking dish.
Step 2: The “Sheet” Slice: Without pulling the rolls apart, slice the entire sheet of buns in half horizontally using a long serrated knife. Place the bottom half in your baking dish.
Tip: Keeping the rolls connected while slicing and baking prevents the filling from falling out and helps the rolls steam slightly inside, keeping them incredibly soft.
Step 3: Build the Layers: Evenly layer the corned beef across the bottom buns, then top with the Swiss cheese slices. Place the top half of the rolls back on.
Step 4: The Butter Brush: Brush the melted butter generously over the tops.
Tip: If you want to break the “4-ingredient” rule for a huge flavor boost, whisk a teaspoon of Dijon mustard or a sprinkle of poppy seeds into the melted butter before brushing.
Step 5: The Two-Stage Bake: Cover the dish loosely with foil and bake for 12–15 minutes.The Finish: Remove the foil and bake for an additional 2–3 minutes. This allows the tops of the buns to get that perfect, golden-brown toast while the cheese stays molten underneath.
