Experimenting with @runpunkrun's lemon bars

[sonia]

As I commented to runpunkrun after I tried their Dairy-free Lemon Bar recipe, the bars taste good, but they differ from the unexpected canonical lemon bar in my head.

This personal canonical lemon bar has a crust more like shortbread, denser and softer at the same time, and more off-white. Filling creamier and less sweet. I have no idea where or when I had it, but the image of it is clear, complete with waxed paper under it from the bakery.

Things I have learned while experimenting with this recipe:

• I am an engineer, not a scientist. Obviously I should have changed one thing at a time and held everything else constant until I achieved what I wanted. What I did is use available ingredients and eyeball quantities and see how it turned out. At least I took some notes!
  
• My intuition about what to change works a lot better for the filling than the crust.
  
• The kind of oil matters.
  
• The kind of citrus matters.
  
• Buy an extra lemon. Not all lemons are equally juicy.
  
• My cat likes lemon bars. Who would have thought! I left a full pan cooling on the counter, and when I came back the top looked different... like it had been... licked???

Crust
I had bought some cassava flour on sale, so first I tried substituting cassava flour for the almond flour by weight. I knew almond flour absorbs less liquid by volume, but it turns out it absorbs less liquid by weight too. I ended up adding 1/2 cup of water to get the batter the right consistency. The crust turned out rubbery but edible.

The next time I put in half as much cassava flour, and still had to add water. Then I realized that I've been using the coconut oil that's been in the refrigerator forever as my neutral oil. I heated it in the microwave to make it liquid, but I think it was making the batter more dry overall. I switched to sunflower oil this last time.

I went back to mostly almond flour, even though it's not the consistency I want. I need to learn more about gluten-free flours before I try again. I did change the ratio of almond flour to cassava flour, and added an egg. The batter came out a little too moist, but the bars taste fine.

New ingredients (so far):
1 cup almond flour
1/2 cup cassava flour
1/8 cup powdered sugar
1/4 cup neutral oil (sunflower)
2 large eggs
zest from one lemon ~1 teaspoon
1/2 tsp fine salt (except what I have is coarse salt so I totally eyeballed this)

Filling
I wanted the filling to be creamier, less sharp, and less sweet. So I decreased the sugar, increased the GF flour, and added an egg, and used the same methods. That's been working great.

New ingredients:
1/2 cup granulated sugar
1/4 cup GF flour
1/2 (heaping) tsp baking powder
3 large eggs
1/4 cup lemon juice

I was tempted by Meyer lemons at the farmer's market one week, and Persian limes the next week. Turns out the Persian limes are sharper than I like. The Meyer lemons are great in this recipe!

I ran out of cassava flour and used tapioca starch instead, which is finer. Possibly coincidentally, it took a little longer to bake the filling.

Note to self: USE THE OVEN MITTS! One time I wasn't paying attention and just grabbed the hot handles of my glass pan to put the crust + filling in the oven. Fortunately I dropped the pan back on the stove top without spilling anything, and it had cooled just enough not to give me blisters.


If anyone has suggestions on how to get the crust more the way I want it, I'm all ears! Any gluten-free baking experiments you want to share?