Preheat oven to 350° F.
In the bowl of a stand mixer fitted with a dough hook, mix together the flour, yeast, sugar and salt. Slowly add the water and olive oil and continue mixing until the dough forms a ball and has pulled away from the sides. If the dough is too sticky, add flour 1 teaspoon at a time.
Transfer the dough to a large, lightly oiled bowl and cover with plastic wrap. Allow the dough to rest and double in size, approximately 1 hour.
Transfer to a lightly floured surface and divide the dough into 2 equal pieces. Form each piece into a ball and allow to rest 10 minutes before rolling out. If storing for later, lightly coat each dough ball with olive oil and store in a zip top bag for up to 5 days.
Gently punch down the dough and turn it out onto a lightly floured work surface. Roll the dough out into a 20x11 inch rectangle. Spread the Pepper and Onion Relish over the surface of the dough in an even layer to coat and sprinkle with the mozzarella cheese. Cut the rectangle into five equal strips then stack them on top of each other. Cut the stack into four equal pieces so you have 20 squares total.
Line the squares against each other and place in a loaf pan coated with cooking spray cut side down. There will be space on each side of the bread. Cover with plastic wrap and allow to rise for 30 minutes.
Transfer the loaf pan to the oven and bake for 15 minutes. Brush the top with melted butter and sprinkle with parmesan cheese. Return the pan to the oven and continue baking for 15 to 20 minutes or until golden brown.
Remove the pan from the oven and cool on a wire rack for 10 minutes before turning out on a serving plate. Serve immediately.
