- Preheat oven to 400 degrees. Lightly spray 4 six inch sub molds with cooking spray. (If no molds see my article on how to make molds out of foil or line an 8 x 4 inch loaf pan with parchment paper) Set aside 
- In a small bowl combine the mozzarella and parmesan cheese then set aside 
- In a large mixing bowl sift or whisk together all the dry ingredients except topping until there are no lumps 
- Stir the eggs in until all the dry ingredients are moist. Add the oil and stir to combine. Add the warm water and stir until a soft dough is formed 
- Form dough into a smooth ball and massage for 2 minutes to absorb any extra moisture 
- Divide dough into 4 portions. Roll each portion into an oval shape and press evenly throughout the prepared sub molds 
- Brush tops of dough with the melted butter if you are wanting a toasted top. Sprinkle the desired amount of the cheese mixture over the top of the bread 
- Place into preheated oven and bake at 400 degrees 15 to 20 minutes or until golden and a tester comes out clean. If making in a loaf pan bake at 350 degrees for 45 to 50 minutes 
- Remove from the oven. Allow to cool in the pan at least 15 minutes to firm up. Remove from the molds and transfer to a wire rack. Allow to cool completely before slicing 
- Once cooled slice each sub bread in half to create a top and bottom bun. Store leftovers in an airtight container at room temperature up to 4 days