Prep Rolls – Line a 13 x 11-inch baking sheet with tin foil, then lightly grease the foil with olive oil. Cut a stack of cooked country ham slices into quarter-size pieces. Fill each roll with ample pieces of country ham slices and grated swiss cheese. Then, place the filled rolls close together on the foil-lined baking sheet.
Make Sauce – Melt a stick of butter in a microwave-safe bowl in your microwave for about 30-45 seconds until fully melted. Add 1-2 TBSP mustard (to taste), 1 TBSP dried minced onion, and 1 TBSP poppy seeds to the bowl and mix thoroughly with the butter.
Bake rolls – Cover the rolls with tin foil and place the baking sheet in the refrigerator for at least 3 hours. This allows the sauce to blend with rolls, however, you can bake them immediately. When ready to bake, preheat the oven to 350 degrees F. Remove the foil cover and bake for approximately 30 minutes. Watch carefully so that they do not scorch. Once about 30 minutes are up, remove it from the oven. Let rest for a few minutes, then serve. Yields about 8 servings.