Red Truck Bakery's Time-Tested Birthday Cake – Garden & Gun

Ingredients

• 1½ cups unbleached all-purpose flour, plus more for dusting
• 1 cup sugar
• 8 tbsp. (1 stick) unsalted butter, at room temperature
• 2 large egg whites
• 2 tsp. pure vanilla extract
• 1¾ tsp. baking powder
• ½ cup whole milk
• 4 large eggs whites
• Pinch kosher salt
• 5 oz. unsweetened chocolate, chopped