Make the Cake:

1. Preheat oven to 350°F (175°C). Grease and flour an 8-inch round cake pan.
2. In a bowl, cream butter and sugar until light and fluffy.
3. Beat in eggs one at a time, then add vanilla extract.
4. In a separate bowl, whisk flour, baking powder, and salt.
5. Alternate adding dry ingredients and milk to the butter mixture, beginning and ending with dry ingredients.
6. Pour batter into the prepared pan and smooth the top.
7. Bake for 30-35 minutes, or until a toothpick inserted in the center comes out clean. Let cool completely.

Prepare the Cream Filling:

8. Whip heavy cream with powdered sugar and vanilla extract until soft peaks form. Set aside.

Prepare the Blueberry Topping:

9. In a saucepan, combine blueberries, sugar, and lemon juice.
10. Cook over medium heat for 5-7 minutes, stirring occasionally, until the blueberries soften and release their juices. Let cool.

Assemble the Cake:

11. Slice the cooled cake in half horizontally to create two layers.
12. Spread whipped cream filling over the bottom layer.
13. Spoon the blueberry mixture on top, then place the second cake layer over it.
14. Optionally, add extra whipped cream and blueberries for decoration.

Serve:

15. Slice and serve chilled for the best flavor!