Step 1 Heat oven to 400° F. Roll the pizza dough into a 14-inch circle and cut into 8 triangles. Step 2 Stack a slice of ham and cheese and some onion on the bottom of each triangle and roll the dough up around the filling. (Some will stick out the ends.) Step 3 Transfer the rolls to a parchment-lined baking sheet. Bake until golden and crisp, about 20 minutes. Step 4 Combine the mustard and oil in a medium bowl and toss with the romaine. Serve with the turnovers.