Do compare this with the earlier recipe for Marble/Marmer Cake. Both recipes are noticeably generous with the use of eggs, but this one has fewer ingredients. Most importantly, this recipe doesn’t include any raising agent, which indicates that the rise is completely dependent on:
a) the creaming process – remember to cream butter and sugar till extremely light & fluffy, and add the egg yolks a teaspoonful at a time to prevent emulsifying;
b) the whisked egg whites – beat till ‘medium peak’ stage where the whites are still glossy and smooth but distinct marks are left by the whisk as you beat and when lifted, the peaks can hold their shape for a while (this is before you get to ‘hard peak’ stage where the tips of the whites are more pointed). Baking at Home with The Culinary Institute of America says,
This is the ideal stage for foams to be folded into batters… since the whites are still flexible enough to expand without bursting as they get hot.
And of course, fold in the flour and whisked egg whites very gently to prevent knocking out the air from the batter.
There are no instructions for doing the marbling, but of course, grandmother knew the technique well enough not to have to write it down in these notes to herself. One way to do it is to remove a third of the batter, add in the cocoa powder. Then pour the cocoa batter into the bowl of plain batter and swirl lightly before pouring the mix into a baking tin.
Speaking of baking tins, grandmother’s recipes often don’t specify the size of baking tin to be used. According to British cooking guru, Delia Smith, this is a typical problem of heirloom recipes:
One of the primary reasons why cakes sometimes fail is the recipe itself. It might be wrong or simply too vague, like some of grandma’s hand-me-downs which never mention details like tin sizes or oven temperature.