Preheat the oven to 350 degrees. Spray a 9 by 5-inch bread pan with cooking spray and set it aside.
Cut the pepperoni pieces into quarters and set them aside.
In a large bowl, add the flour, baking powder, baking soda, salt, and pepper. Stir these ingredients with a whisk or a fork to combine them.
In a smaller bowl, mix together the eggs, oil, and buttermilk. Set this aside.
To the bowl with the flour mixture, add the parmesan, mozzarella, and pepperoni, stirring to coat these ingredients with the flour mixture.
Add the egg mixture to the bowl containing the flour mixture. Stir just until the wet ingredients are incorporated and there are no areas with dry flour in the mixture. If you over-mix the batter, the bread may turn out tough.
In a small dish, combine the tomato sauce, ½ teaspoon Italian seasoning, garlic powder, and onion powder, stirring to combine.
Add half of the batter to the loaf pan, spreading it to cover the bottom of the pan in an even layer. Top this half of the batter with the tomato sauce mixture, spreading it in an even layer.
Spread the second half of the batter over the top of the tomato sauce in an even layer. Sprinkle the top of the batter with 1 teaspoon of Italian seasoning. If you want, you can sprinkle a bit of extra Parmesan cheese on the top of the loaf.
Place the loaf pan in the preheated oven and bake it for 45 to 55 minutes or until a knife or cake tester inserted in the center comes out clean. Allow the bread to cool for about half an hour before removing it from the pan. Use a spatula or a butter knife to loosen the bread from the pan and turn it out onto a plate.
Slice the bread with a serrated knife and serve warm. Store leftovers tightly wrapped in aluminum foil in the refrigerator for up to five days. This bread is perfectly reheated in a toaster oven to give it a crispy, toasted texture.