Preheat oven to 350 degrees.
Line a square baking dish with parchment paper.
I find this step very important for once bars are cooled it is easy then to lift the whole bar from the pan and then slice.
In a medium bowl use a hand mixer to combine the gluten free flour blend, vegan “butter” and icing sugar until it resembles coarse sand.
Press into the square baking dish.
Bake in the oven for about 20 minutes until lightly brown.
Remove and cool while you are preparing filling
In a small bowl beat the eggs, zests, lemon and lime juice, salt and baking powder with a hand mixer until light and foamy.
Pour filling over crust and place bake in oven for 20-25 minutes.
Cool on counter and then place in refrigerator to chill for a bit.
Slice and serve!!