In a saucepan or a microwave-safe bowl, combine the chocolate, butter, sugar and salt. Either on the stovetop or in the microwave, melt everything together until smooth and glossy.

Remove from the heat and stir in the cocoa powder. Mix well until smooth.

Allow the chocolate filling to cool to room temperature. It will thicken slightly to reach a nicely spreadable consistency.

I recommend making the dough using a stand mixer fitted with the dough hook attachment, but you can also make it by hand.

Make the psyllium gel: In a bowl, mix together the psyllium husk and lukewarm water. After about 30-45 seconds, a gel will form.

In a large bowl or the bowl of a stand mixer (if using), whisk together the tapioca starch, millet flour, sorghum flour, sugar, instant yeast, baking powder, xanthan gum and salt.Tip: If using active dry yeast instead, you need to activate it first. Mix it together with a tablespoon of the sugar and 80g (⅓ cup) of the water listed in the recipe (note that that means you'll use less water to make the psyllium gel). Set aside for 5-10 minutes, or until the mixture starts frothing. Then, add it to the dry ingredients along with the rest of the wet ingredients.

Add the egg, egg yolk and oil to the psyllium gel and mix well to combine.

Make a well in the middle of the dry ingredients and add the psyllium gel-egg mixture.

Knead the dough until smooth and all the ingredients are evenly incorporated, then knead for a further 4-5 minutes (if using a stand mixer) or 6-8 minutes (if kneading it by hand). Use a rubber spatula to occasionally scrape along the sides and bottom of the bowl to prevent any dry patches of unmixed flour.Tip: This extra kneading time will make the dough EXTRA smooth, which is the key to a beautiful gluten free babka.

The final dough will be sticky to the touch – that’s okay, you’ll be working on a lightly floured surface so it shouldn’t be a problem. Resist the temptation to add more flour to the dough, as that can make the final babka too dense and dry.Tip: If you find the dough too sticky to easily handle (even on a floured surface and with floured hands), you can chill it in the fridge for about 1 hour before proceeding to the next step. This will make the dough firmer, less sticky, and therefore easier to handle.

Line a 9x5-inch (23x13cm) loaf tin with parchment/baking paper and set aside until needed.

Turn out the dough onto a lightly floured surface and shape it into a ball, then roll it out into a large 12×18-inch (30x45cm) rectangle.Tip: I like to roll my babka dough fairly thin, this ensures a multitude of dough-filling layers for an extra decadent end result.

Dollop on the chocolate filling and, using a small offset spatula, spread it out into an even layer all the way to the edges.Tip: If your filling has thickened too much while you were preparing the dough, you can reheat it very briefly, just to loosen it slightly.

Roll up the dough into a 12-inch (30cm) log and arrange it so that the seam faces down.

Use a lightly oiled, sharp serrated knife to cut the log lengthwise in half. Tip: Oiling the knife ensures that the dough and filling won’t stick to it, resulting in a cleaner, neater cut.

Turn the two halves so that the cut sides face upwards, and then twist the two strands around each other. (See blog post for photos.)

Carefully transfer the babka into the lined loaf tin. You might need to gently squish the ends of the braid towards the centre, to make the babka fit into the loaf tin – that's okay.

Lightly cover the loaf tin with a sheet of plastic wrap/cling film (to prevent it from drying out) and proof in a warm spot until doubled in size, about 1 hour 15 minutes to 1 hour 30 minutes. Tip: If your kitchen is on the cold side, put a cup of boiling hot water into your (turned-off) oven – that will create the perfect warm, slightly humid proofing environment.

Adjust the oven rack to the lower middle position and preheat the oven to 350ºF (180ºC).

Once the babka has doubled in size, brush it gently with the egg wash.

Place the loaf tin on a baking sheet (to catch any drips) and bake at 350ºF (180ºC) for 55-60 minutes until the babka is deep golden brown on top. If it starts browning too much or too quickly, you can cover it with a sheet of aluminium foil, shiny side up, and continue baking until done (I usually cover it after about 20-25 minute in the oven).I like to check the doneness by inserting a toothpick into the centre of the loaf, much like you would with a cake: if your toothpick comes out with raw dough on it, the babka needs a bit longer in the oven.

While the babka is baking, prepare the sugar syrup. In a small saucepan or a microwave-safe bowl, combine the sugar and water. Heat them either on the stovetop or in the microwave until the mixture only just comes to a boil and the sugar has fully dissolved. Set aside and allow to cool completely.

Immediately out of the oven, while your babka is still hot, brush it generously with the sugar syrup – the more syrup you use, the sweeter the crust.

Allow the babka to cool in the loaf tin for about 10 minutes, then remove it out of the tin onto a wire rack.

Enjoy warm or cooled completely to room temperature.

This gluten free chocolate babka is definitely at its best fresh, on the day of baking, but it also keeps really well for 3-4 days at room temperature in a closed container or well wrapped (to prevent it from drying out).I recommend reheating it before serving, either in a microwave or in a 350ºF (180ºC) oven, just to return it to its original softness.