In a mixing bowl, combine finely chopped fresh parsley, cilantro, and minced garlic. Drizzle in ¼ cup of olive oil and 2 tablespoons of red wine vinegar. Add a pinch of salt, black pepper, and red pepper flakes to taste. Mix well and let the flavors meld for at least 10 minutes.

Preheat your oven's broiler to high. Slice the thick French bread loaf in half lengthwise and place it cut-side up on a baking sheet lined with parchment paper.

Spread the chimichurri sauce generously over the cut sides of the bread.

Sprinkle shredded mozzarella over the chimichurri-covered bread, followed by a sprinkle of grated parmesan.

Broil the bread for about 5-10 minutes, watching closely until the cheese is bubbly golden brown and the edges are crispy.

Remove from the oven, cool for a minute, then slice and serve warm.