Using Food Chopper, chop bell pepper and onion. In 10-inch frying pan, heat oil over medium heat until hot. Press garlic into oil. Add bell pepper onion and 1/2 teaspoon of the oregano leaves. Cook and stir 3-4 minutes or until vegetables are crisp- tender. Remove pan from heat.
Unroll 1 pizza crust onto lightly floured surface. Using lightly floured roller, roll out crust to 12 x 9-inch rectangle; cover with half of the beef, cheese and vegetable mixture to within 1/2 inch of edges of dough.
Starting at longest side of rectangle, roll up dough, jelly-roll fashion; press seam together to seal. Repeat with remaining crust and filling ingredients.
Place rolls, seam sides down, on 15-inch round baking stone. Join ends of rolls together to form 1 large ring; press ends together to seal. In small bowl, combine egg white and water; brush onto dough using pastry brush.
Sprinkle with the remaining 1/2 teaspoon oregano. Bake 20-25 minutes or until golden brown. Let stand 10 minutes before cutting into wedges.