I was going to use this delectable banana cake recipe to talk to you about how I clearly have an obsession with baking rotten bananas into yummy treats (see here, and here!) but I realized that I haven't yet done a post where I really dig into substituting gluten free flours for all-purpose flour, and this recipe is a classic example of how easy it is to switch to gluten free in your baking.
When I first discovered my serious health issues with gluten, I started baking gluten-free as most people do: I bought pre-mixed gluten-free blends at the store. There is nothing wrong with pre-mixed blends. In fact, when I'm feeling lazy I have three different King Arthur GF blends that I reliably and successfully turn to. However, as I got used to eating gluten-free I realized that the guar gum and xantham gum found in store-bought blends cause some of the same digestional issues I had from eating gluten. Those gums had to go! Only problem was, those gums are there for a reason. They help hold up the baked goods in the same way gluten does, by providing structure. Luckily there's a binder that is a good alternative to xantham gum: psyllium husk. You need to use 4x as much psyllium husk as xantham gum in a recipe (use 1 tsp psyllium husk per cup of flour called for), but other than that, it does just as good a job, plus it has the added benefit of being a natural fiber source.
So if you too have decided you need to try to make your own gluten-free blends instead of relying on the pre-mixed ones, the one thing you MUST have is a scale. You absolutely CANNOT expect to turn a gluten-recipe into a GF one without a scale (unless you are using a store-bought cup-to-cup blend.) In general baking terms, weighted ingredients are much more accurate, and will give you tasty results each time. Measuring by volume with cups is not only less accurate it is also more time-consuming. Once you get used to it, you will never go back. Additionally, measuring with a scale is even more important for GF baking because the best way to replace all-purpose flour in a recipe is to replace it with the same WEIGHT of alternate GF flours. So if a recipe calls for 1 cup of all-purpose flour, you can just get out your scale and spoon in a few spoonfuls of a whole bunch of different gluten-free flours until you get to 120 grams and that (plus 1 tsp of psyllium husk) will be your substitute.
Now which flours work best for what? In general terms, white rice flour, almond flour and sourghum flour are the best GF flours to substitute for all-purpose flour. If a recipe calls for cake flour I use a mix of white rice flour, sourghum flour, tapioca flour, and cornstarch. If a recipe calls for bread flour I use brown rice flour, sourghum flour, potato starch*, and tapioca flour. When making pancakes and muffins (the easiest things to make gluten-free!) I like to experiment with different blends but love using brown rice flour or almond flour as the main flour with smaller proportions of buckwheat flour and/or millet flour (both are flours made from seeds.) There are some flours that really mess with a recipe because they absorb too much liquid. Coconut flour and potato flour* are ones that do this and I would not try to use either of these flours when replacing all-purpose flour in a recipe. Other flours like quinoa flour, teff flour, pistachio flour and hazelnut flour, have very strong flavor profiles so you should also proceed with caution there. Teff flour and buckwheat flour both pair well with chocolate but generally should not be used as the only flour when substituting for all-purpose flour. When baking a cake that gets most of its structure from beaten egg whites or beaten whole eggs, such as angel food cake, chiffon cake, genoise cake, or really any cake at all that involves you folding egg whites into the batter, or beating whole eggs for a very long time (sometimes a chiffon or genoise cake recipe is not labeled as the type of cake it is), you should NOT use psyllium husk in those recipes, and white rice flour by itself is the best substitute.
I hope that was a good introduction to flour substitution for those of you adventuring into the promising and tasty world of gluten-free baking! I packed a lot of information into just a three paragraphs so if you have any questions or need clarification leave a comment and I will see if I have an answer for you. All in all, making a recipe gluten-free is super easy. Especially when you are making a butter-cake based recipe like the one below, that is chock full of sweetness and flavor, no one will know that it is gluten free. Of course, as in gluten baking, it helps to have a good understanding of basic baking techniques, to have an accurate, well-performing oven,** and to not ever, ever over bake!
*Potato starch and potato flour are two totally different flours with completely different properties, they are not replaceable for each other and should not be confused with each other.
** If your oven is on the older side, I highly recommend buying an oven thermometer so that you know exactly what temperature your oven actually is. It can often be 100 degrees or more off of what the dial says!
Gluten Free Banana Rum Cakes with Caramel Sauce
adapted very slightly from Sweet by Yotam Ottolenghi and Helen Goh
If you don't need these to be gluten free then simply substitute 110 g of all-purpose flour for the white rice, sorghum and psyllium husk. But I promise you, these babies are perfection and no gluten-eater would be able to tell these apart from a gluten-filled one.
Sugar work can be tricky but the caramel sauce is TOTALLY worth the minimal extra effort. Just read the instructions very carefully twice over before even thinking of starting the sauce if you've never made caramel before.
All ingredients should be at room temperature, but it is particularly important for the butter to be poke-a-hole-through-with-your-finger soft.
I used a mini bundt pan that made six small bundt cakelets. Each cake was enough for two people so next time I will use my extra-mini bundt pan that makes twelve small bundt cakelets. Use whatever muffin or small cake pan you have but make sure you adjust the baking time accordingly and do not overbake.
Ingredients:
100 g unsalted butter, at room temperature
70 g granulated sugar
70 g brown sugar
2 large eggs
1 tsp vanilla
100 g almond flour
1/8 tsp salt
1/2 tsp cinnamon
3/4 tsp baking soda
1 1/2 tsp baking powder
1 tsp psyllium husk
60 g white rice flour
50 g sourghum flour
230 g peeled, mashed, overripe bananas (from about 3 smaller bananas)
100 g sour cream
2 tbsp dark rum
For Rum Caramel Sauce:
200 g granulated sugar
1/2 cup (120 ml) water
1/2 cup plus 2 tsp (130 ml) heavy cream
1 1/2 tbsp dark rum
Generously grease your mini bundt pan or muffin pan with butter and preheat the oven to 350 with a rack in the middle of the oven.
In a stand mixer fitted with the paddle attachemnt, beat the butter and both sugars for about 3 minutes, until pale and fluffy. Beat in the eggs, one at a time and mixing well after each addition. Stir in the vanilla.
In a small bowl combine the bananas, sour cream and rum.
In a large bowl measure out and then whisk together all the dry ingredients until very well combined (about 2 minutes of thorough whisking.)
Add the sour cream and flour mixtures in three alternate additions to the butter mixture, mixing until thoroughly combined after each addition.
Spoon the batter into the prepared pans, until each is 3/4 full. Bake for anywhere from 12-28 mins (depending on the size of the pans you used), until the tops spring back lightly when touched with your fingertip or a toothpick inserted into the center of a cakelet comes out clean. Set the cakes aside to cool completely before taking them out of the pans.
Caramel:
While the cakes are baking make the caramel. Stir the sugar and water together in a medium sized saucepan (the size of the pan is important.) Put the pan on the burner and turn the heat to medium-high. Do not stir or touch the syrup once you turn on the heat. You can tilt the pan to swirl around the sugar but do not stir. Bring the mixture to a boil and simmer for 8-10 minutes, or until the syrup turns a deep amber color. Immediately remove the pan from the heat when it turns this magically color. Stir in the rum, and then very, very slowly stir in the heavy cream bit by bit. Set the caramel aside for 30 minutes before pouring over the cakelets.
