Preheat the oven to 400°F (200°C).
Roll out the pizza dough on a floured surface into a rectangle.
Combine the Dijon mustard, mayonnaise, garlic powder, and black pepper in a bowl.
Spread the mixture evenly over the rolled out dough.
Layer the sliced ham and shredded Swiss cheese over the sauce.
Sprinkle Italian seasoning over the ham and cheese.
Starting from one end, roll the dough tightly around the filling.
Pinch the ends of the dough to seal and place it seam-side down on a baking sheet.
Brush the top of the Stromboli with the beaten egg.
Bake in the preheated oven for 25-30 minutes or until golden brown.
Let it cool for a few minutes before slicing and serving.
