Preheat your oven to 350°F (175°C). Grease and flour a 9×13 inch baking pan.

In a large mixing bowl, cream together the softened butter and granulated sugar until light and fluffy, about 3-4 minutes.

Beat in the eggs one at a time, ensuring they’re fully incorporated before adding the next. Stir in 1 teaspoon of vanilla extract.

In a separate bowl, whisk together the flour, baking powder, baking soda, and salt.

Gradually add the dry mixture to the butter-sugar-egg mixture, alternating with the sour cream. Start and end with the dry ingredients.

Fold in 1 and 1/2 cups of fresh blueberries.

Evenly spread the batter into the prepared baking pan and sprinkle the remaining blueberries on top.

Bake in the preheated oven for 30-35 minutes or until a toothpick inserted into the center comes out clean.

Allow the cake to cool in the pan for about 10 minutes before transferring it to a wire rack to cool completely.

In a mixing bowl, whip the heavy cream with powdered sugar and remaining vanilla extract until soft peaks form.

Spread the whipped cream over the cooled cake, or serve it by the slice with a dollop of whipped cream.