Preheat your oven to 350°F (175°C).

Line a sturdy baking sheet with parchment paper or aluminum foil to catch any drips.

Place your sourdough loaf on a cutting board. Using a serrated bread knife, carefully slice the bread in a grid pattern. First, slice in one direction about 1 inch apart, not slicing all the way through the bottom crust. Rotate the bread 90 degrees and slice again to create a diamond or square pattern. You should have a grid of bread cubes, all still attached at the base.

In a small saucepan, melt the butter over medium-low heat. Add minced garlic and cook for 1-2 minutes until fragrant. Don't let the garlic brown.

Remove from heat and stir in the chopped herbs, salt, and black pepper. Whisk until combined. Your kitchen will smell divine.

Gently pry open the cuts you made in the bread. Using a spoon or pastry brush, drizzle the herb butter mixture deeply into all the crevices. Be generous — every piece wants to be coated. Some butter will run down the sides and that's perfectly fine.

After using half of the butter, stuff the grated Parmesan cheese and optional shredded mozzarella cheese down the cuts. Then drizzle the remaining butter over the top.

Carefully transfer the loaded loaf to your prepared baking sheet. Wrap it loosely in aluminum foil to keep the inside soft and steamy as the cheese melts.

Bake for 15-20 minutes until warmed through and cheese is melted. Then remove the foil and bake another 10-15 minutes until top is golden and crispy.

Let cool on baking sheet for a few minutes before placing on a large platter and serving.