1. In a mixing bowl, whisk together the butter and sugar until it turns from yellow to white. This is known as "creaming". Preheat your oven to 375 degrees F.
2. Add the eggs and mix until it is almost all the way combined.
**Chef's Tip** Do not overmix your eggs in cakes! This will cause cracking in the final product! This includes cheesecakes!
3. In a separate bowl, mix your flour, baking powder, and salt. Sift if you have one available. Add half of this mixture and half of the milk to the egg mixture.
4. Mix again until it is nearly combined and repeat with the remaining ingredients. Finish by gently folding in the blueberries.
5. Spoon this batter into your balsamic sugar baking dish gently. Be sure not to disturb the blueberries and the glaze.
6. Gently press down to flatten out the batter across the pan. Do this until it is evenly dispersed. Be sure not to pull or spread the batter with a pulling motion. This will disrupt the berries on the bottom.
7. Fill the baking dish 3/4 of the way full and place in your preheated oven. Rotate the pan every 5 minutes.
8. Depending on the size of the pan, this will be finished in 15-25 minutes. Use a cake tester or a tooth pick to poke a hole in the center. If it comes out clean, it is finished.
9. Once finished, cool it down on the counter top. Once it has cooled, gentle release the sides of the cakes with a butter knife.
10. Place a plate or tray over the top and carefully flip it over. Remove the baking dish slowly and evenly.
11. You should see beautiful rich and jammy looking berries in an even pattern across your cake with loads of blueberries bursting from the sides.