Quickly rub together the flour, salt, cold lard, sugar, lemon zest, cinnamon and cloves, then add the egg and work into a smooth dough. If too crumbly, add one or two tablespoons of sour cream.
Divide the dough into two equal pieces, wrap each in cling film, and chill for 20 minutes.
Roll out one half onto a parchment-lined baking tray to about finger thickness.
Spread the jam evenly over it.
Roll out the other half of the dough on a floured surface and cut into long strips, which you arrange in a lattice pattern over the jam layer.
Brush the lattice with beaten egg.
Bake in a 180°C preheated oven for about 25-30 minutes, until light golden brown.
While still warm, cut into squares or rectangles.
Based on: Malatinszky Fanny szakácskönyve (a classic Hungarian cookbook), modernised. Calories and protein are estimated.