Heat oven to 350°. Combine flour, sugar and butter in a large bowl. Pat mixture into a 8" tart shell pan. Bake tart shell in oven until just browned, about 10-12 minutes.

Heat oven to 350°. In a mixing bowl add granulated sugar, lemon peel and juice. Beat until mixture thickens and is smooth, about 5 minutes. With mixer running, add flour and baking powder and mix until well-blended, about 3 minutes. Pour lemon mixture into tart shell and bake in oven for 20 minutes or until pastry edge is golden and lemon mixture is set. Remove from oven and let cool.

To serve, cut lemon tart into wedges. Using a sifter, sprinkle tart with powdered sugar. Serve with either whipped cream or vanilla ice cream.