Preheat oven to 400°F. Line a baking dish with parchment paper.
Sauté onion and bell pepper over low-medium heat for 5 minutes. Add steak, break apart, and cook until done. Stir in Worcestershire sauce and seasonings. Remove from heat and mix in provolone until melted.
Melt butter and mix with garlic and parsley.
Roll pizza dough into a rectangle. Brush half the garlic butter on dough. Add cheesesteak mixture to one side and sprinkle with half the mozzarella. Fold dough over to seal.
Brush remaining butter on top, lightly score into strips, add remaining mozzarella, and bake 15–20 minutes until golden.
Mix mayo and sriracha for dipping. Slice, serve, and enjoy