Before you start, make sure all your ingredients are ready. I shredded the chicken, cooked the bacon until crispy, and grated my cheeses. Having everything prepped makes assembly so much smoother.
On a lightly floured surface, roll your pizza dough into a large rectangle. I like it thin enough to fold without tearing but thick enough to hold the filling.
In a small bowl, mix the shredded chicken, cream cheese, ranch, garlic powder, and black pepper. Spread the mixture evenly over the dough, leaving about an inch border. Then sprinkle bacon, mozzarella, and cheddar on top.
Carefully roll the dough like a jelly roll, tucking in the edges as you go. Seal the seam well to prevent the filling from leaking out during baking.
Brush the beaten egg over the top for a beautiful, golden finish. I always do this step because it makes the stromboli look restaurant-quality.
Place on a parchment-lined baking sheet and bake at 375°F (190°C) for about 25 minutes, or until the crust is golden and crispy. Let it cool slightly before slicing.