Vatrushka

Whisk the flour, yeast, the 50g of sugar for the dough and the salt together in a large bowl.

Whisk the egg for the dough into the lukewarm milk and pour it in.

Mix to a shaggy dough, then knead for 8-10 minutes, until smooth and elastic.

Work in the softened butter a piece at a time, kneading until the dough is glossy and comes away from the bowl again.

Cover and prove at around 24C/75F for 60-90 minutes, until doubled.

Meanwhile, check the tvorog. If it is wet, drain it in a muslin-lined sieve for 2 hours before using — a loose filling boils up over the wall of dough and floods the tray.

Press the curd through a sieve to smooth it, then beat in the egg yolk, the 60g of sugar for the filling, the semolina, vanilla and lemon zest.

The semolina is there to take up residual whey as the buns bake, not for bulk. Leave it out and the filling weeps into the crumb underneath.

Chill the filling while the dough finishes proving.

Knock the dough back and divide it into 10 pieces of about 75g.

Roll each into a tight ball, then flatten it into a disc about 9cm across on a lined tray, spaced 5cm apart.

Prove for 30-40 minutes, until puffed and slow to spring back.

Heat the oven to 190C/375F.

Dust the base of a small glass with flour and press a well into each bun, going almost down to the tray and leaving a rim about 1.5cm wide.

Use the glass rather than your fingers. A fingertip gives an uneven hollow with a thick patch in the middle that rises and pushes the filling out.

Spoon about 45g of the curd into each well, levelling it with the rim.

Brush only the rim with the beaten egg. Egg on the filling sets to a shiny skin that cracks as it cools.

Bake for 16-20 minutes, until the rim is deep gold and the filling is just set with a slight wobble at the centre.

Take them out while the centre still moves. Baked until firm all through, the curd cracks, dries and tastes chalky.

Cool on the tray for 15 minutes; the filling firms as it cools.

Eat the same day. The enriched crumb stales quickly.