For the crust, mix the butter into the flour and sugar until well combined (I used my hands for this step).
Press into a 13 x 9 x 2-inch greased baking dish (you can line your baking dish with greased aluminum foil which will help you cutting the bars later).
Bake at 350°F for 20-25 minutes or until lightly browned.
While the crust is baking, make the filling. Beat together eggs, sugar and lemon juice.
Sift together flour and baking powder and stir into egg mixture.
Pour over baked, semi cooled crust.
Bake at 350°F for 20 minutes.
Cool (even chill in the fridge for a few minutes) and sprinkle with powdered sugar.
Cut into bars (if you lined your baking dish with aluminum foil, put the aluminum foil out with the bars and cut on a flat surface).