To start, combine the flour, yeast, salt, sugar. Garlic powder, dry milk in a bowl of a stand mixer or a large bowl. Mix everything, and then add the water and oil to the dry ingredients. Stir until the dough comes together into a shaggy mass. Transfer the bowl to the mixer and attach the dough hook and knead on medium-low speed until smooth and elastic. Another way to tell if the dough is ready is when the dough pulls away from the sides of the bowl. If the dough is sticky and sticks to the sides of the bowl, add more flour, 1 tablespoon at a time until the dough leaves the side of the bowl. This will take about 5- 7 minutes. You can Knead the dough by hand, and it will take about 7 – 10 minutes.
Transfer the dough into a lightly oiled bowl and cover the bowl with plastic wrap. Allow the dough to rise in a warm place for about 1- 2 hours or until it doubled in size. You can leave the dough to rise in the refrigerator overnight. After the dough has risen, punch it down and divide the dough into 2 and roll each dough into a ball. If you are not ready to use the pizza dough, coat the pizza dough with olive oil and place it in the freezer bag. Refrigerate for up to 2 days.
Preheat oven to 425° F and line a baking sheet with parchment paper or a silicone mat. Set aside.
Shaping the dough: On a lightly floured surface, stretch and roll 1 pizza dough into a 10 by 16-inch rectangle into ¼ inch thick. Spread the surface with pizza sauce, layer the meat and cheeses evenly over the pizza sauce leaving a 3-inch gap on the top and a 1-inch border around the edges. Brush the edges with the egg wash mixed with Italian seasoning.
Roll it up by folding the bottom parts towards the top parts creating a wide log, tucking in the ends like a cinnamon roll. Pinch the seam tightly to seal (check the video for visual explanation). Transfer the stromboli to the prepared baking sheet, seam side down. Brush the top of the stromboli with the remaining egg wash and cheese. Cut a slit on top of the roll for steam to escape.
Bake in a preheated oven for about 12-15 minutes or until golden brown, then allow to cool down for about 10 minutes. Transfer the stromboli to a cutting board and slice the stromboli into an inch thick. Serve them warm with marinara sauce, dipping sauce, or plain.
Cover and store leftover stromboli in the refrigerator for up to 7 days