Preheat oven to 350 degrees. Lightly grease a 10x15 cookie sheet or jelly roll pan and line with greased waxed paper or parchment paper
Beat eggs, salt and pepper until well blended. Pour into prepared pan and bake for 10-15 minutes or until set.
When the eggs are done, invert themonto a piece of foil, and gently peel off the waxed paper or parchment paper. Spread a thin layer of mustard on top of the baked eggs. Layer with meat and cheese. Top with onions. Roll up the eggs jelly roll fashion and wrap it tightly in foil. Place the roll onto the cookie sheet.
Return the wrapped roll to the oven and bake for an additional 10 minutes until the cheese is melted.
Carefully remove the foil. Slice the roll into 6 thick slices. Serve immediately on its side so you can see the pretty cut side.