Decadent rustic bread - Le Coup de Grâce

Ingredients

• 1/2 red onion, finely sliced
• 1/2 yellow onion, finely sliced
• 3 tablespoons olive oil
• 1/4 cup Belgian type white fruity beer
• 2 pinches dried thyme
• 1 big round bread loaf 500g, cut in crosshatch but keeping the base
• 1/4 cup butter
• 3 garlic cloves, finely chopped
• 1/3 cup fresh parsley, finely chopped
• 1 cup mozzarella cheese, grated
• 1 cup gruyere cheese, grated
• 5 cooked bacon slices, cut in 3 chunks each
• 10 chive sprigs, finely chopped
• Salt and ground pepper