Preheat your oven to 350°F and line a 9x13-inch baking dish with parchment paper. Take 12 Hawaiian sweet rolls and cut them horizontally in half using a long serrated knife in one smooth motion. Keep the top slab and bottom slab intact instead of pulling apart individual rolls. Place the bottom slab of rolls cut-side up inside the prepared baking dish so it forms an even bread base. (I tried cutting individual rolls the first time, the assembly took forever and the cheese melted out everywhere. Keep the slab whole.) Cut the rolls whole so the filling spreads evenly and stays warm inside.

Layer 6 slices of Swiss cheese across the bottom roll slab so they overlap slightly and cover the edges. Fold 1 pound of thinly sliced honey ham into ruffled ribbons and spread them evenly over the cheese. Top the ham layer with the remaining 6 slices of Swiss cheese to lock the meat in. Look for full coverage across the entire bread surface so every single bite gets meat and cheese. You'll see two layers of pale cheese trapping the pink ham in the middle. Double cheese layers act as glue to seal the moist ham inside during baking.

In a small bowl whisk 1/2 cup melted unsalted butter with 1 tablespoon Dijon mustard, 1 teaspoon Worcestershire sauce, 1 teaspoon onion powder and 1 tablespoon poppy seeds. Place the top slab of rolls over the ham and cheese layer. Pour or brush the golden brown butter glaze evenly across the top rolls so it drips down the sides. The rolls will look glossy and saturated with dark poppy seeds sticking to the crusts. You'll smell the sharp tang of mustard and garlic immediately as the warm butter coats the sweet bread. Glaze every square inch of crust so the bread bakes up crisp rather than dried out.

Cover the baking dish tightly with aluminum foil and bake at 350°F for exactly 15 minutes. Remove the foil and bake uncovered for another 10 minutes until the cheese is completely melted and the tops are deep golden brown. You'll hear the butter sizzle along the dish edges and see gooey white cheese bubbling out between the layers. The bread top turns crisp and fragrant with toasted poppy seeds. Uncover for the last 10 minutes so steam escapes and the glazed tops turn crisp.