Notes: Use pre-baked dinner rolls. They usually come in a sheet of 12 rolls, stuck together. If you use this type (She likes the sweet whole wheat ones by King's Hawaiian) She said she didn't have parsley or poppy seeds and she didn't refrigerate overnight. She also used horseradish/Dijon store bought mayo.
•3/4 cup (1-1/2 sticks or 12 Tablespoons) butter
•1/4 cup sweet onion, minced
•2 Tablespoon poppy seeds
•1/2 teaspoon garlic powder
•1 Tablespoon Worcestershire sauce
•2 Tablespoons hot or spicy mustard
•1/4 cup brown sugar
•1 Tablespoon chopped parsley
•24 (about 2 x 2-Inches each) small dinner rolls (see Note)
•Horseradish mayonnaise (see Note)
•24 (about 3/4 pound) thin slices of deli ham (see Note)
•24 (about 1/2 pound) thin slices of Swiss cheese
Line two 9 x 13-inch baking pans with non-stick foil or butter traditional pans.
To prepare marinade, saute minced sweet onion in butter over low heat until onion is soft and translucent. Add poppy seeds, garlic powder, Worcestershire sauce, mustard, and brown sugar. Stir until brown sugar is melted into the sauce. Remove from heat and stir in parsley. Set marinade aside to cool while you assemble the buns.
Slice the buns in half. Spread bottoms of buns with a thin layer of horseradish mayonnaise. Fold ham slices to fit the bottom of each bun. Repeat with Swiss cheese slices, folding to fit buns. Replace bun tops. Place ham and cheese buns into prepared baking pans. Pour marinade evenly over both pans of buns. Cover tightly with foil. Refrigerate overnight.
Preheat oven to 350 F. Bake marinated buns covered for 25 minutes. Remove foil and bake an additional 10 minutes.