There are a few good recipes for making lemon bars on the Food Network provided by Ina Garten and the Food Network Kitchen. Another good lemon bars recipe from Taste of Home has a basic flour, butter and sugar crust with a filling made with both lemon juice and zest.
Make classic lemon bars by blending 1 1/2 sticks of unsalted butter with 2 cups of all-purpose flour, 1/4 cup of light brown sugar, 1/2 cup of confectioners' sugar and 1/4 teaspoon of salt. Press the crust into the bottom of a baking pan, and cook at 350 F for 25 minutes. Prepare the filling by combining 4 eggs, 2 egg yolks, 2 cups of granulated sugar and 1/3 cup of all-purpose flour. Once the batter is smooth, stir in 1 teaspoon of lemon zest and 1 cup of fresh lemon juice. Pour the lemon filling on the crust, and bake at 300 F for another 30 minutes.
A good yet simple recipe uses a crust made only from 1 cup of all-purpose flour, 1/2 cup of softened butter and 1/4 cup of confectioners' sugar. After baking the crust at 350 F for 20 minutes, add the filling made from 2 eggs, 1 cup of sugar, 2 tablespoons of all-purpose flour and the zest and juice from a lemon. Bake for another 25 minutes, and dust with confectioners' sugar before serving.