1/2 cup butter
2 tablespoons brown sugar
1 cup rolled oats
1 teaspoon vanilla extract
1/4 cup lemon juice
1/2 cup lemon zest
Preheat oven to 350 degrees F (175 degrees C). Grease and flour 2 9-inch round pans.
In a large bowl, cream together the butter, brown sugar, oats and vanilla until light and fluffy. Stir in the lemon juice and lemon zest. Pour the batter into the prepared pans.
Bake in the preheated oven for 30 minutes. Cool completely in pan and remove from pan. When cool, make a double batch of the icing. Frost the outside of the cake with frosting. Immediately drizzle frosting over the cooled cake while still warm. Refrigerate 2 hours before cutting into squares.