To make the dough, put the yeast, 55g warm (43C) water and 1tsp of the sugar in the bowl of a stand mixer. Whisk together and leave to rest for 5-7 minutes until foamy.
Add the milk, eggs, vanilla, flour, remaining sugar and the salt. Attach the dough hook and knead on a low speed for 4-5 minutes until well combined. Cover with a tea towel andleave to rest for 10-15 minutes.
Using your hands, make a hole in the middle of the dough. Put the butter into it, close the dough over it, then knead on a medium-low speed for 10 minutes, periodically scraping down the sides of the bowl. Cover with a tea towel and leave to rest for 5-6 minutes.
Knead again for 7-10 minutes until the dough looks smooth and shiny and no longer sticks to the sides of the bowl. As a check, do a ‘windowpane test’: roll a small piece of dough into a ball and stretch it thin without letting it tear. Next, hold it up to a light source – if you can see light passing through it, your dough is fully kneaded. If it’s not ready, continue to knead, rest and test, repeating until it is.
Very lightly flour a work surface, then use the ‘slap and fold’ kneading method: firmly hold the dough at the top with both hands then slap it on to the table. Fold it in the middle,rotate your hands, and repeat 5-7 times until smooth.
Next, round the dough: place your hands on either side of it with the edges of your palms against the surface. Holding your left hand as a guide, use your right to lightly push the outer edges of the dough underneath while turning slightly. Continue this motion until it forms a smooth ball with a round top. Carefully lift the dough ball on to your left hand, maintaining the round shape, and place in a large bowl with the open edge facing down. Cover the bowl with cling film and rest at room temperature for 30-45 minutes.
Put the bowl in the fridge and leave to rest for 2-4 hours until doubled in size.
Make the chocolate paste. Put the butter and chocolate chips in a small bowl, then microwave in 30-second bursts, or place over a pan of simmering water, stirring, until fully melted.
Add the cocoa powder, icing sugar, coffee and salt. Whisk until well combined, then set aside to cool to room temperature.
Put the dough on a lightly floured work surface. Using a knife or bench scraper, divide into two equal pieces, then roll one into a 35x30cm rectangle.
If the chocolate paste is too thick to spread, warm it in the microwave for just 10 seconds to soften it slightly. Spread it evenly over the dough with an offset spatula. Starting from a long side, tightly roll the piece of dough into a log. Transfer the roll to a baking sheet and repeat with the second piece of dough. Put the baking sheets in the freezer for 5-10 minutes so the dough can be easily cut. Use a sharp breadknife to cut the first log lengthways down the centre, so you have two halves with the chocolate showing. Place both pieces next to each other, chocolate side facing up. Begin twisting the two ropes around each other, stretching slightly and keeping the chocolate side up, until you have a long braid. Using your hands, seal the ends so they do not come apart.
Place the braid carefully into a 20x12x6cm loaf tin. Repeat the slicing and braiding process for the other log. Cover lightly with cling film and leave to rest at room temperature for around 45-60 minutes until risen by half.
Preheat the oven to 175C/155C F/Gas 21⁄2.
Bake for 30-40 minutes until the tops brown and the braids reach an internal temperature of 90C on a cook’s thermometer. (You can test if they feel firm to the touch, or if a toothpick pushed into the dough comes out clean, but it’s better to use a thermometer.) If the tops are browning too quickly, place a small piece of foil over them.
Make the caramel syrup. In a small pan, heat the sugar over a medium-low setting, watching the pan but without touching it. Once the sugar has melted and begins to lightly caramelise, add 110ml water. Reduce the heat to low and cook for 1-2 minutes, stirring occasionally, until fully dissolved. Allow to cool.
Remove the babka from the oven and leave to cool in the tin for 10-15 minutes. Brush the caramel syrup over while still in the tin, then brush once again just before serving, if you like. Store in an airtight container at room temperature for 2-3 days.
Recipes and photographs taken from Turkuaz Kitchen by Betül Tunç, photography by Betül Tunç (Square Peg, £25)
