Preheat your oven to 350°F (175°C) and grease a 9-inch round cake pan.

Cream the softened butter and granulated sugar together until light and fluffy.

Incorporate the eggs one at a time, mixing well after each addition.

Sift together the flour, baking powder, and salt.

Whisk together the milk, lemon juice, lemon zest, and vanilla extract until combined.

Gradually mix the dry ingredients into the butter mixture, alternating with the wet mixture.

Pour the batter into the prepared pan and bake for 30-35 minutes.

Allow the cake to cool in the pan for 20 minutes, then transfer to a wire rack.

Once cool, slice the cake in half horizontally and layer with lemon custard.

Dust with powdered sugar before serving.