01 -
Preheat oven to 200°C. Heat a large pan over medium-high heat and add vegetable oil.
02 -
Add sliced steak to the pan, season with salt and black pepper, and cook for 2 to 3 minutes. Add onion, green pepper, and mushrooms. Sauté an additional 2 to 3 minutes until onions are lightly browned.
03 -
With a rolling pin, roll one half of the dough into a 23 x 33 cm rectangle, leaving a 1.25 cm margin along the edges.
04 -
Spread half of the cooked steak mixture down the center of the dough. Top evenly with mozzarella and optional provolone. Fold the sides, tuck, and roll tightly to form a filled loaf.
05 -
Arrange stromboli seam-side down on a greased baking sheet or lined with aluminium foil. Brush the top with beaten egg. With a sharp knife, cut several 5 cm slits in the top to allow steam to escape.
06 -
Transfer the baking sheet to the oven and bake for 15 to 20 minutes until the crust is golden brown.
07 -
Remove from oven, let cool slightly, slice into portions, and serve immediately with a dipping sauce if desired.