Preheat heavy bottomed pan (I use cast iron) to medium-low heat.
Add slices of mortadella-as many as can easily fit in the pan without touching.
Allow mortadella to cook for 1-2 minutes, then mound 1 oz. of mozzarella in the middle of each mortadella slice, and cover with another slice of mortadella.
When the top slice of mortadella starts to droop and the mozzarella begins to melt, gently press the top layer of mortadella down onto the bottom layer. Sprinkle with dried rosemary.
Carefully flip over with a spatula.
The hot pocket is finished when both sides are wrinkled and crisp and the mozzarella is melted.
Alternately; allow the hot pockets to come to room temperature, then freeze tightly covered in the freezer. To eat from frozen, heat 1-2 minutes in the microwave at 70% power, or warm in the oven at 300ºF for 15 minutes.