Poppy Seed Sweet Bread (potica)

To make filling, place milk, butter, sugar and poppy seeds in a saucepan over medium heat. Cook, stirring, for 10 minutes or until milk is almost absorbed. Cool, then stir in jam, egg yolks, vanilla, breadcrumbs and lemon zest.
Whisk egg whites to soft peaks, then fold through poppy seed mixture in 3 batches. Set aside for 30 minutes to thicken slightly. Whisk egg yolks until they start to thicken. Stir in 250 ml lukewarm milk, 55 g caster sugar, and oil, and set aside.
Combine 2 tbsp flour, yeast, remaining 60 ml milk and 1 tbsp sugar in a bowl until combined. Stand in a warm, draught-free place for 10 minutes or until the mixture bubbles.
Combine 700 g flour, lemon zest, remaining 55 g sugar, vanilla and 1 tsp salt in the bowl of an electric mixer fitted with a dough hook. Mix yeast and egg mixtures into the flour mixture on low speed until mixture forms a sticky dough. Mix in enough of the remaining 50g flour to form a soft dough. Increase speed to medium–high and knead dough for 6 minutes or until it’s smooth and elastic.
Place dough in a greased bowl and set aside in a warm, draught-free place for 1 hour or until it doubles in size.
Turn out onto a floured work surface and shape into a log. Roll out to a 3 mm-thick, 62 cm x 45 cm rectangle. Spread over filling, leaving a 2 cm border. Roll up lengthwise like a Swiss roll. Cut into 2 logs. Place side by side so each log touches a long edge of a buttered 5 cm-deep, 21 cm x 31 cm slab pan. Cover with a tea towel. Stand in a warm, draught-free place for 50 minutes or until dough doubles in size.
Preheat oven to 160°C. Bake potica for 1 hour or until golden and a skewer inserted in the centre comes out clean. It will keep wrapped in paper towel, in an airtight container, for up to 4 days.