Follow these easy steps to create your Juicy Blueberry Upside Down Cake:

1. Preheat Oven: Preheat your oven to 350°F (175°C). Grease a 9-inch round cake pan.
2. Make the Topping: In a small saucepan over low heat, melt ½ cup of butter. Stir in the brown sugar until well combined. Remove from heat.
3. Prepare the Berries: Evenly distribute the fresh blueberries across the bottom of the greased cake pan. Pour the butter and brown sugar mixture over the blueberries.
4. Mix Dry Ingredients: In a bowl, whisk together the flour, baking powder, baking soda, and salt. Set aside.
5. Cream Butter and Sugar: In a separate bowl, beat the softened butter and granulated sugar until light and fluffy.
6. Add Eggs and Vanilla: Mix in the eggs one at a time, then add the vanilla extract. Continue to beat until well blended.
7. Combine Ingredients: Gradually add the dry ingredients to the wet mixture, alternating with buttermilk. Mix until just combined.
8. Pour Batter: Carefully pour the cake batter over the blueberry topping in the pan, ensuring it covers the berries evenly.
9. Bake: Place the pan in the oven and bake for 40-45 minutes or until a toothpick inserted into the center comes out clean.
10. Cool: Once baked, remove from the oven and let the cake cool for about 15 minutes.
11. Invert the Cake: Run a knife around the edges, then carefully invert the pan onto a serving plate.
12. Serve Warm: Allow the cake to cool slightly before serving warm or at room temperature.

These straightforward instructions will guide you in creating this delicious and beautiful cake.