Preheat oven to 400 degree F. Line a large baking sheet with foil or parchment paper; grease foil and set aside. In a large skillet cook sweet peppers and garlic in hot butter over medium heat about 5 minutes or until tender, stirring occasionally. Stir in the crushed red pepper, 1/2 teaspoon salt, and 1/4 teaspoon black pepper; set aside to cool slightly.
In a medium bowl stir together the mozzarella, ricotta, and basil. Stir pepper mixture into cheese mixture until well combined; set aside. On a lightly floured surface roll out pizza dough to a 16x10-inch rectangle. Cut into two 8x10-inch rectangles. Spoon half of the pepper mixture along one of the long sides of one dough rectangle, leaving a 1-inch border along the long side and a 1/2-inch border along the short sides. Spread pepper mixture to a width of about 3 inches. Fold one long side over the pepper mixture. Seal seam and ends, tucking seam under the loaf. Carefully place on prepared baking sheet. Repeat with remaining dough and filling.
With a sharp knife cut 4 diagonal slits in the top of each loaf. Brush loaves with egg. Bake for 15 to 18 minutes or until golden brown. Let stand 10 minutes. Slice each in half and serve warm. Makes 4 servings.