Hi Astrid, here's a link to a post where I describe the steps behind developing this recipe: https://bakeschool.com/developing-a-gluten-free-cake-the-process/

Thanks for your comments. I don't think I was clear enough about how I used the mashed potatoes. I boiled a bunch of peeled potatoes until they were very soft, then I passed them through a ricer to "mash" them. I let the mashed potatoes cool completely (adding no butter, nor any milk), and then when they were cooled, I weighed out what I needed and added it to the cake batter.

The potatoes I used had a yellow flesh and were round. They weren't called Yukon Golds, but I suspect they are a very similar type, which is a less floury, more moist.

I used the sorghum flour to help reduce the amount of moisture in the cake batter. I made several attempts before trying sorghum (which is a good, general gluten-free flour that many gluten-free bakers like to use). I suspect even millet would work (or perhaps even rice flour or potato flour), but the texture and mouthfeel would be different. The sorghum was affordable (especially compared to the xanthan!).

As for the pan size, with this quantity of batter, the springform pan was more than 3/4 full, so it took longer to bake, and I personally find it more difficult to get a fully, well cooked center when the cake pan is so full.

Hope this helps and if you need anything more, let me know!

Hi! Thanks for stopping by! You are right. As somebody else pointed it out, it wasn't clear what "type" of mashed potatoes I used.
Basically, I boiled the peeled potatoes til they were nice and soft, and then I passed them through a ricer. I let the "mashed" potatoes cool completely before weighing out what I needed and adding them to the cake batter. So, the mashed potatoes were plain: no milk and no butter.

Hope that helps 🙂

In using the mashed potato, do you let it fully cool down or do you use it fresh and warm? In Irish potato pancakes, it makes a big difference as chilling the potato retrogrades the starch preventing gumminess. Also, you are correct that using different potatoes will give drastically different results due to their very different starches. The use of a waxy potato in potato pancakes make for a horribly dense and gummy outcome. It can be difficult just looking at a picture to know if you used a waxy (I suspect not) a floury (like russet and others) or something in the middle. Can you be more precise in the type of potato you used. Also, what does the sorghum flour do for the recipe? It is not something I usually have on hand. Why did you think baking in the 9" cake pan is easier or better than the 8" springform other than the shorter time?

Your cake looks lovely. I would never have thought that mashed potatoes was the secret ingredient. I am looking forward to making it and sieving it to my family. Thanks for sharing.