How to go about converting this blondie recipe to gluten-free

Question

Below are ingredients for blondies, which I have made several times to pleasing results.

I've had a friend ask that I make her a pan of gluten-free blondies but I am not sure how to go about doing that to maintain consistency.

I made her a cake once, and the only differences between most cakes were the GF flour, and what seemed to be a larger set of eggs. That cake, by the way, came out dry in my opinion.

Could anyone please let me know how I might make this gluten free? Thanks!

• 2 cups all-purpose flour
• 1 teaspoon baking powder
• 1/4 teaspoon baking soda
• 1 teaspoon salt
• 3/4 cup butter (solid/chilled; salted or unsalted)
• 1 cup light brown sugar packed
• 1/2 cup granulated sugar
• 2 eggs lightly beaten
• 2 teaspoons vanilla extract
• 1/2 C peanut butter

Answer 1

You might want to check out this website: https://glutenfreeonashoestring.com/. The author has lots of recipes (including more than one recipe for blondies) and advice on both commercially made and DIY gluten-free flours. Which GF flour you use matters and different flours are best for different types of baked goods. I've made her GF flaky pie crust a few times and it turns out great.

If you are going to convert the recipe above, you'll most likely want to add xantham gum, increase the moisture content slightly, and possibly increase the leavening agents (baking powder and baking soda).

Many GF recipes include xantham gum, either in the flour itself or as an additional ingredient if your flour doesn't include it. Xantham gum provides elasticity and stickiness.

According to https://www.tasteofhome.com/article/converting-recipes-to-gluten-free/ (and based on your comment about a previous recipe you tried to convert), you should also increase the moisture content, either by adding an egg, full fat milk, or buttermilk, or substituting some of the liquid in the recipe with sour cream or mayonnaise. This site also has some good advice on converting recipes to GF: https://theheritagecook.com/converting-recipe-gluten-free/.

For this recipe, there isn't much moisture besides the eggs and peanut butter, so you wouldn't replace any of that with something else. I would add something — maybe 1/4 cup or less of applesauce or apple butter. The flavor would be mild and compatible with the other flavors. Or you could use dark brown sugar (instead of light brown), which will have more moisture content. Another option might be to add a tablespoon of molasses.

The last site also suggests increasing the leavening a little. I'm not sure if you'd need to do this with this recipe, though, unless you prefer your blondies to be more cakey than fudgey. Given that there is peanut butter in the recipe already, I'm guessing this is a fudgey blondie. I've never tried to make a change to the leavening in a recipe, so I have no advice on how much you would add.

Answer 2

You cannot maintain consistency when converting a recipe to being gluten free. A more realistic goal is to hope that it comes out pleasant to eat, as opposed to "raw in the middle" or "falls apart into crumbs/powder".

The most practical method is to purchase a gluten-free substitute flour, either an "all purpose" or "cup for cup" labelled one, or one that is specifically meant for batters, e.g. with "for cakes" on the label. Then try out baking the recipe, and cross your fingers - your chances are quite good, maybe 80%.

If it doesn't work, I am afraid that there are no general guidelines for improving the result. It is more of a process of trial and error, while being very pedantic about keeping notes between attempts. You can still use general cake-making guidelines, of course, since eggs, sugar, etc. still keep their roles. It is simply that any increases or decreases can have an unexpected side effect on either cohesiveness or baking-through, which simply means that you have to give up on what would otherwise have been a good idea. Also, as an additional dimension, you can vary the flour mixes, using either different commercial ones, or published mix-it-yourself ones, and see if some happen to work better than others. It is not a predictable process though, just a matter of testing everything through.

Answer 3

With cakes and breads changing to gluten free makes a large change in consistency, dessert bars like blondies and especially brownies on the other hand are much more forgiving of the change as they are dense to begin with. I would do a direct substitution from regular flour to a gluten free blend without any other changes.

I would go for a blend rather than a straight-up rice, potato or other type of gluten free flour because a good blend will be formulated to give the closest absorbancy and other factors to plain flour. You can buy tapioca, maize and other gf flours and blend your own, my personal experience is that the blends these days, at least available where I live, are pretty good and I don't think I'll do better without a great deal of experimentation.