Preheat your oven to 350°F (175°C).
In a microwave-safe bowl, combine the chopped Hershey’s Milk Chocolate Bars and butter. Microwave in 30-second intervals, stirring in between, until melted and smooth. Let it cool slightly.
In a large mixing bowl, add the melted chocolate and butter mixture. Stir in the granulated sugar until well combined. Then, add the eggs one at a time, mixing well after each addition. Pour in the buttermilk, chocolate syrup, and vanilla extract, mixing until everything is incorporated.
In another bowl, whisk together the cake flour and baking soda. Gradually add the dry ingredients to the wet mixture, folding gently until just combined. Be careful not to overmix; a few lumps are okay.
Pour the batter into the prepared baking pan and spread it evenly. Bake in the preheated oven for 30-35 minutes, or until a toothpick inserted in the center comes out clean. Let the cake cool in the pan for about 10 minutes before transferring it to a wire rack to cool completely.
Once the cake is completely cool, dust the top with powdered sugar for a beautiful finish. Slice, serve, and enjoy your delicious Hershey Bar Cake!