Cake like a Greek Tsoureki stuffed with Nutella

1.  Combine milk, yeast and 1 tbsp sugar in the bowl of an electric mixer fitted with a paddle and set aside in a warm place until foamy (5-7 minutes). Add 75gm flour, mix to combine, then add eggs, yolk, remaining sugar and a pinch of salt, mix to combine. While mixing on low speed, gradually add remaining flour until combined, then add 150gm butter, a little at a time, beating until dough is shiny and elastic (3-5 minutes; dough will be quite soft). Place dough in a lightly oiled bowl, cover with oiled plastic wrap and set aside until doubled in size (1-1½ hours).

2.  Preheat oven to 180C. Place hazelnuts on a baking tray and roast until golden (5-7 minutes), cool slightly, then rub with a tea towel to remove skins and cool completely. Process in a food processor until coarse crumbs form, combine with remaining softened butter to form a paste and set aside at room temperature until required.

3.  Knock back dough and divide into two. Working with one half at a time, roll dough on a lightly floured surface into a 20cm x 32cm rectangle. With longest side facing you, spread over half the hazelnut paste, leaving a 4cm-border, then scatter over half the chocolate. Roll away from you to form a cylinder, brush ends with a little eggwash, then join ends to make a loop, twist into a figure of eight and place in a 9cm x 19cm loaf tin lined with baking paper. Set aside in a warm place until dough reaches the top of tin (1 hour). Repeat with remaining dough. Brush babkas with eggwash, scatter with demerara sugar and bake in centre of oven until golden and cooked through (35-40 minutes). Cool in tins for 10 minutes, then turn out, cool on a wire rack and serve warm or at room temperature. Babkas will keep, stored in an airtight container, for 3 days, and are best served warm or in toasted slices.