A classic: These are one of my favorite 'bar' cookies. Light shortbread base, with a moist lemon-custard topping dusted with powdered sugar. These use only 1 cup of GF flour for a 8 x 8 pan, so it's a pretty cost-effective GF dessert.
Mixture of my mother's recipe and Connie Sarros' take in Gluten-Free Dessert Cookbook.
My fellow labmates have been asking me to bring some of these in since March, when I first mentioned their sour-sweet goodness. None of them are Celiac and they didn't even notice these were made without wheat. It makes me so happy to bake for friends.
Makes 16 square bar cookies.
-8 x 8 square baking pan (glass, preferred)
-large mixing bowl
-small mixing bowl
-zester (a very fine grater, used for fruit rinds)
1 stick (1/2 cup) butter, softened; I used Earth Balance Buttery Sticks to make this lactose-free
-- 1 cup GF flour blend (next four ingredients), unleavened --
1/4 c. tapioca starch
1/4 c. potato starch
1/2 c. white rice flour
1 heaping tsp. xanthan gum
1/4 c. powdered (confectioner's) sugar
Zest of 1 big lemon
Juice of 1 big lemon (no less that 2 tbsp.)
1 c. white granulated sugar
3/4 tsp. baking powder
pinch of salt
1. Take butter out of fridge and set into your large mixing bowl; let soften (DO NOT melt the butter in the microwave.. be patient). Use the butter wrapper and grease up the 8 x 8 baking pan. Preheat your oven to 350 degrees F.
2. In small mixing bowl, combine tapioca starch, potato starch and white rice flour with xanthan gum and powdered sugar. Mix carefully, but completely, with a spoon. Let sit.
3. Go back to the big bowl. Begin beating the softened butter with an electric mixer until it is smooth (around 1 minute). Carefully add in the flour mixture to the butter, 1/4 cup at a time. Stir a little with a spoon/spatula before mixing again with the electric beater (it will go everywhere, trust me). Beat the combined flour/butter mix until fully moistened-- this batter will look crumbly, but should keep shape when pinched between your fingers.
4. Press the 'crumbly' shortbread batter evenly into the greased 8 x 8 pan with your fingers. Once you have a smooth, uniform surface (press well to make it stick), slide the cookie crust into the preheated oven. Bake for 20 minutes-- DON'T FORGET TO REMOVE ON TIME!
5. While the shortbread is baking, wash out your large mixing bowl and beater prongs with hot water. Also wash out your small mixing bowl.
6. Scrub the large lemon very well with hot water (Celiacs: cut off the fruit sticker). Remove the top yellow rind from the fruit with a zester. Don't zest too much and get any of the white pith. Place zest in small bowl-- you should have maybe ~1/2 tsp.
7. Cut the zested lemon in half and remove the seeds, if you can. Squeeze both lemon halves over the small bowl, accumulating no less than 2 tbsp. lemon juice. Be sure to catch and remove any errant seeds.
8. In large mixing bowl, crack open both eggs and add in white granulated sugar. Add in the baking powder and a little salt. Scrape the lemon juice/zest mix from the small to the large bowl. Beat the eggs/lemon until frothy (1-2 minutes) and sugar is mostly dissolved (mixture will be viscous).
9. Remove cooked shortbread base from the oven at the 20 minute mark. Pour/spoon the egg/lemon mixture over the cooked base and return cookies to the oven. Bake for another 20 minutes, or until the top forms a tan skin.
10. Remove from oven and chill overnight. Serve cold with a dusting of powdered sugar.