Preheat your oven to 350°F (175°C). Grease and flour a 9-inch round cake pan.
In a medium bowl, toss the blueberries with 1 tablespoon of granulated sugar and set aside.
In a large mixing bowl, cream together the softened butter and remaining granulated sugar until light and fluffy, about 3-4 minutes.
Add the eggs one at a time, mixing well after each addition, then stir in the vanilla extract.
In another bowl, whisk together the flour, baking powder, and salt.
Gradually add the dry ingredients to the wet mixture, alternating with the blueberries, and mix until just combined.
Pour the batter into the prepared cake pan and smooth the top.
Bake for 30-35 minutes or until a toothpick inserted in the center comes out clean.
Allow the cake to cool in the pan for 10 minutes before transferring it to a wire rack to cool completely.
While the cake cools, whip the heavy cream with the powdered sugar and lemon juice until soft peaks form.
Once the cake is cool, spread the whipped cream over the top and garnish with additional blueberries if desired.