Preheat an oven to 425 F and move the oven rack to the top 1/3 of the oven. Line a baking sheet with parchment paper and set aside.
Make the sauce. Heat the olive oil in a small saucepan. Once the oil is shimmering, add the minced garlic, oregano, and red pepper flakes and cook for 1-2 minutes, stirring often, until fragrant. Add the crushed tomatoes and sugar and season to taste with salt and pepper. Simmer 15 minutes.
Mix the butter. Combine the room temperature butter, parsley, basil, garlic, onion powder, parmesan and pepper in a small bowl. Mix until well combined.
Prep the bread. Cut the French bread loaf in half lengthwise and place on a baking sheet lined with parchment. Spread the butter evenly between bread halves. Bake for 5 minutes. While the bread is in the oven, pat the diced whole milk mozzarella very dry with paper towels
Assemble and bake. Remove the bread from the oven and top with pizza sauce, shredded cheese, fresh mozzarella, and pepperoni. Return to the oven for 10-15 minutes, until the cheese is melty and pepperoni is crispy. Serve right away.