Pre-heat oven to 350F (180C). Line a 12 cup muffin tin with cupcake liners.
In a medium bowl sift together the flour, baking powder and salt.
In a large bowl beat on medium speed the butter and sugar until creamy (2-3 minutes).
Beat in the eggs one at a time. Add the vanilla and zest and best to combine.
Add the flour and beat just to combine. Do not over beat.
Add the lemon juice and the milk alternately, beating just until combined (just until the batter is smooth). Again do not over beat.
Fill the prepared muffin / cupcake tin 3/4 full and bake for about 20 minutes. Let cool 5-10 minutes in the pan then move to cool completely on a wire rack before frosting.
FOR THE FROSTING
In a medium bowl add the cream and whip until soft peaks appear, continue beating on medium speed while adding half the sugar and lemon juice combine, then add the remaining sugar and lemon juice increase speed to high and beat until thick.