Slice party rolls in half horizontally.

Evenly distribute the minced canned ham over the bottom halves of the rolls.

Sprinkle grated Swiss cheese generously over the ham.

Place the top halves of the rolls over the cheese.

In a small pan, melt the margarine over medium heat.

Add the chopped onion to the melted margarine and sauté until softened.

Stir in the prepared mustard and Worcestershire sauce into the sautéed onion mixture.

Brush the mustard-Worcestershire mixture evenly over the tops of the rolls.

Preheat oven to 350°F (175°C).

Place the assembled rolls in the preheated oven and bake for approximately 15 minutes, or until thoroughly heated and the cheese is bubbly and melted.

Remove the rolls from the oven and let them cool slightly before cutting apart.

Serve warm.

For freezing, wrap the assembled, unbaked rolls tightly in airtight packaging.

To bake from frozen, place directly in a 350°F (175°C) oven until heated through and cheese is bubbly.