Preheat the oven to 375°F (190°C). Grease a 9-inch round cake pan or line it with parchment paper.
In a large mixing bowl, whisk together the all-purpose flour, baking powder, salt, and granulated sugar.
In a separate bowl, whisk the whole milk and egg until combined.
Pour the wet ingredients into the dry ingredients and stir until just combined. Do not overmix. The dough will be slightly sticky.
Turn the dough out onto a lightly floured surface and knead gently 3-4 times to bring it together.
Roll the dough into a rectangle approximately 12 by 8 inches.
In a small bowl, mix the softened butter, minced garlic, chopped parsley, dried oregano, salt, and black pepper until well combined.
Spread the garlic butter mixture evenly over the rolled-out dough.
Sprinkle the shredded mozzarella cheese evenly over the garlic butter layer.
Cut the dough into 1.5-inch squares (about 24 squares).
Stack the squares in piles of 3-4 pieces each, then place the stacks upright and close together in the prepared pan, arranging them so they fill the pan.
Brush the top of the dough stacks with the remaining 4 tablespoons of melted butter.
Bake in the preheated oven for 18-20 minutes, or until the bread is golden brown and cooked through.
Remove from the oven and let cool for 5 minutes before serving. Pull apart the bread pieces and enjoy warm.