Generally this would be applesauce (minhag America), sour cream (minhag Galitzia)”
What if you follow the minhag to do both, so as not to be mevayeish anyone’s minhag?
Also,since no one ever eats just ONE donut, do we have to wash and make hamotzee and bensch afterward? Some people bake yeast-raised donuts, to lessen the fat content. Does the same halacha apply whether it is fried or baked? I really cannot wait until Purim for these (heart)burning answers.