01 -
Position your oven rack up top and heat to 425°F. In a medium saucepan over medium-low heat, melt the butter with 3 tablespoons olive oil. Add your minced garlic, pepper flakes, and oregano, cooking until the garlic softens but doesn't brown (about 2 minutes). Mix in half the herbs and a generous pinch of salt, then remove from heat.
02 -
Split your bread lengthwise and crosswise, then place it cut-side-up. Using a baking sheet, gently press down to compress it to about 2/3 of its original height. Transfer to the baking sheet and brush half of your garlic-herb butter mixture evenly over the cut surfaces.
03 -
Add crushed tomatoes to the remaining garlic-herb butter in the pan. Bring to a simmer over medium heat, then reduce to low and cook until it thickens, about 15 minutes. Season with salt to taste.
04 -
While the sauce cooks, spread 1/4 of the mozzarella over the bread and bake until it just starts to melt, about 8 minutes.
05 -
Spread your sauce over the bread, top with remaining mozzarella, and bake until the cheese melts and starts to brown (about 10 minutes). Finish by sprinkling with Parmigiano-Reggiano, remaining herbs, and the last tablespoon of olive oil. Let it cool briefly before serving.