I tried an eggless hot milk sponge cake, sticking with the KAF proportions but substituting the egg with 1/8 cup yogurt and an extra 1/4 tsp baking powder (meant to also add some baking soda but forgot).
Mixed the yogurt and sugar first to dissolve the sugar, then continued per the recipe.
Took 15 mins at 325F.
This has a little less loft than the one with the egg (which I attribute to lack of egg plus missing baking soda) but is as springy and tender as the other.
I spread a little thinned marmalade in the center, to align with the orange accents in the cake (and because I am completely out of jam). This worked nicely, but I did prefer the jam for the swiss roll throwback.
I think the flat top bodes well for a Swiss roll, actually.
Will make again (with 1 tsp baking powder and 1/2 tsp baking soda).
.
