Preheat oven to 375 degrees.

In a bowl, beat together butter and 3/4 cup sugar until light and fluffy, about 2 minutes. Gradually beat in eggs. Stir in lemon zest. Fold in flour, alternately with milk.

Using a small ice cream scoop, scoop batter into mini tart dishes. Place a towel on the counter; then slightly tap each dish onto the towel to level the batter.

Place the dishes on a baking sheet, and bake for 14 minutes.

While the cakes are baking, make the icing. In a small bowl, mix together lemon juice and 1/2 cup sugar. When the cakes have finished baking, spoon the icing over hot cakes. Allow to cool so the icing hardens for a slight crunch.