I recently began making doughnuts. I did a few experiments.
The first time I followed the recipe exactly and they came out perfectly. Large, airy, and soft. But on day 2 they were too dry and lost some of their texture.
To address this problem I did 2 half batches as experiments. One I added too much butter and the other I used my sourdough starter instead of yeast.
None of the butter batch cooked properly. All had raw centres. Only 1/4 of the sourdough batch came out right. The rest were also raw in the centre.
I purposely weighed smaller amounts for my test batches. They were 10-15gr lighter than my first batch. They were also less airy. I fried them the same as far as I can tell.
Why are the smaller doughnuts coming out raw?