Preheat oven to 350°F (175°C). Grease a 9-inch round cake pan.
Cream butter and sugar together until light and fluffy. Beat in eggs one at a time, then add vanilla.
In a separate bowl, whisk flour, baking powder, and salt. Add dry ingredients to wet mixture alternately with milk.
Fold in blueberries gently. Pour batter into prepared pan and bake 35–40 minutes or until golden and set.
Whip heavy cream with powdered sugar and lemon zest until soft peaks form.
Let cake cool, then spread whipped cream on top. Chill briefly before serving.