Smetannik

Heat the oven to 180C/350F.

Butter two 22cm round tins and line the bases with baking paper.

Whisk the eggs and caster sugar together for 3-4 minutes, until thickened and pale.

Whisk in the 200g of soured cream, the honey and the melted butter.

Sift the flour, bicarbonate of soda and salt over the bowl.

Fold until no dry flour is left and then stop.

Stop the moment it disappears. Bicarbonate starts reacting with the acid in the soured cream as soon as the two meet, and a batter beaten hard afterwards has already spent most of its lift in the bowl.

Divide the batter between the two tins and level the tops.

Bake for 22-28 minutes, until deep gold, springy at the centre, and a skewer comes out with a crumb or two clinging but no wet batter.

Cool in the tins for 10 minutes, then turn out onto a rack and cool completely.

Do not try to split a warm sponge. It tears along the knife rather than cutting, and this crumb is soft enough to be unforgiving.

Level the domed tops with a serrated knife and keep the trimmings.

Split each sponge horizontally in two, giving four layers.

Crumble the trimmings between your fingers into coarse crumbs and set them aside.

Chill the mixing bowl and beaters for 10 minutes if the kitchen is warm.

Whip the 600g of cold soured cream with the double cream, icing sugar and vanilla on medium speed for 2-3 minutes, until it holds a soft peak that folds over at the tip.

Whip on medium and stop at soft peaks. Soured cream carries a lot of water and splits into grainy curds and buttery liquid much sooner than plain cream, and once it has split it does not come back.

Set the first sponge layer on a plate and spread a quarter of the cream right out to the edge.

Stack the remaining layers the same way, pressing each one down lightly so the cake does not lean.

Spread the last of the cream thinly over the top and around the sides.

Press the sponge crumbs and chopped walnuts around the sides and scatter the rest over the top.

Cover loosely and refrigerate for at least 8 hours, ideally overnight.

This rest is the recipe, not an afterthought. The layers go in dry and firm and come out damp and soft, and a smetannik cut on the day it is made tastes like sponge and cream sitting next to each other.

Cut with a knife warmed in hot water and wiped dry.

Serve cold, and keep it refrigerated for up to three days.