Prepare the Dough for Italian Stromboli

1. Activate the Yeast: In a small bowl, combine the warm water, sugar, and yeast. Let it sit for 5-10 minutes until it becomes frothy. This ensures the yeast is active and ready for the dough.
2. Make the Dough: In a large mixing bowl, combine the flour, olive oil, salt, and garlic powder. Add the activated yeast mixture and stir until the dough starts to come together.
3. Knead the Dough: Turn the dough out onto a lightly floured surface and knead it for about 5-7 minutes, or until it’s smooth and elastic.
4. Let the Dough Rise: Place the dough in a lightly oiled bowl, cover it with a clean towel, and let it rise in a warm spot for 1 hour, or until it has doubled in size.

Prepare the Filling

5. Shred the Chicken (or prepare other fillings): If you’re using cooked chicken breast, shred it into bite-sized pieces. If you prefer to use another filling like halal pepperoni or sausage, slice it thinly.
6. Prepare the Vegetables: Chop the bell pepper, red onion, and spinach (if using) into small, uniform pieces. This ensures even distribution throughout the Stromboli.
7. Mix the Filling: In a large bowl, combine the shredded cheeses, chicken, vegetables, and Italian seasoning. Season with salt and pepper to taste.

Assemble the Italian Stromboli

8. Preheat the Oven: Preheat your oven to 400°F (200°C) while you assemble the Stromboli.
9. Roll Out the Dough: Once the dough has risen, punch it down and roll it out into a rectangular shape on a floured surface. The dough should be about 12×16 inches.
10. Add the Filling: Spoon the filling evenly across the center of the dough, leaving about 1 inch of space on each side.
11. Roll and Seal: Carefully roll the dough over the filling to form a log, pinching the edges to seal it tightly. You can fold the ends of the dough over the filling for a nice, sealed finish.
12. Apply the Egg Wash: Brush the top of the Stromboli with the beaten egg, which will help it achieve a golden, glossy finish when baked.

Bake the Italian Stromboli

13. Transfer to Baking Sheet: Place the Stromboli seam side down on a lightly greased baking sheet or a sheet lined with parchment paper.
14. Bake: Bake for 30-35 minutes or until the Stromboli is golden brown and the crust is crispy. You can check doneness by tapping the bottom of the loaf—it should sound hollow.
15. Cool and Slice: Let the Stromboli cool for a few minutes before slicing it into thick rounds. Serve it warm, and enjoy!