Blueberry Skillet Cake (a Berry-licious Upside-Down Cake)

Ingredients

• 1 1/2 cups all-purpose flour
• 1 1/2 teaspoons baking powder
• 1/4 teaspoon salt
• 10 Tablespoons butter, Room temperature, divided
• 3/4 cup granulated sugar
• 2 large eggs, room temperature
• 2 teaspoons vanilla extract
• The zest of one large lemon
• 3/4 cup 2% milk
• 1/3 cup dark brown sugar
• 2 1/2 to 3 cups blueberries