**Courtesy of America’s Test Kitchen**

INGREDIENTS

12 rolls, square soft white dinner

6 tablespoons yellow mustard, divided

8 ounces deli Black Forest ham (12 thin slices)

8 ounces deli Swiss cheese (12 thin slices)

Pepper

4 tablespoons unsalted butter

2 tablespoons finely chopped onion

1 tablespoon poppy seeds

2 tablespoons

Worcestershire sauce

1 teaspoon garlic powder

BEFORE YOU BEGIN

We prefer the soft white dinner rolls found in the bakery section of your supermarket, but dinner-size potato rolls will also work in this recipe.

INSTRUCTIONS

1. Adjust oven rack to middle position and heat oven to 350 degrees. Slice rolls in half horizontally. Spread 4 tablespoons mustard on cut sides of roll tops and bottoms. Arrange roll bottoms, cut side up and side by side, in 13 by 9-inch baking dish. Fold ham slices in thirds, then once in half; place 1 slice on each roll bottom. Fold Swiss like ham, then place over ham. Season with pepper and cap with roll tops.

2. Combine butter, onion, and poppy seeds in bowl. Microwave until butter is melted and onion is softened, about 1 minute. Whisk Worcestershire, garlic powder, and remaining 2 tablespoons mustard into butter mixture until combined. Generously brush tops and edges of sandwiches with all of butter mixture. Spoon any remaining solids over sandwiches.

3. Cover dish with aluminum foil and let sit for 10 minutes to allow sandwiches to absorb sauce. Bake for 20 minutes. Uncover and continue to bake until cheese is melted around edges and tops are slightly firm, 7 to 9 minutes. Let cool for 10 minutes. Serve.

4. TO MAKE AHEAD: Sandwiches can be brushed with sauce, covered, and refrigerated up to 1 day in advance. Bring to room temperature before cooking.