In a jug (pitcher), stir together your warm water, yeast and sugar. Allow to stand for 10 minutes until nice and frothy.

In a large bowl or the bowl of a stand mixer, add both flours, the xanthan gum, psyllium husk powder and salt. Mix together until well combined, then add your vinegar, egg white and frothy yeast mixture to the dry ingredients.

Either in a stand mixer fitted with a beater attachment or using an electric hand whisk, mix on a high speed for 3–5 minutes until well combined. It should look like a very thick, sticky batter. Allow to rest for about 10 minutes – this bread batter is very wet, and resting it is super important.

Lightly grease a bread tin (pan), about 26 x 12cm / 10 x 4¾in, and line with non-stick baking parchment.

Pour your rested mixture into the lined tin, ensuring that it’s nicely smoothed out and level. Loosely cover with clingfilm and leave to prove in a warm place for 30-45 minutes, until noticeably risen. Proving can take longer on a cold day, so keep an eye on your loaf!

Preheat your oven to 240°C fan / 260°C / 500°F (or as hot as your oven will go if it doesn’t reach these temperatures). Place a large roasting dish at the bottom of the oven and boil a kettle.

Dust the top of your loaf with a little flour and slash the top of the dough three times using a sharp knife. 

Place in the preheated oven and immediately add a mug’s worth of boiling water to the roasting dish. Bake for 20 minutes, then reduce the oven temperature to 200°C fan / 220°C / 425°F and bake for another 30 minutes, until golden brown.

Remove from the oven. Carefully remove from the tin and tap the base to check that it feels and sounds hollow – if so, then it’s done. Place onto a wire rack and allow to cool completely before slicing.

T I P : If you want an even crustier crust, once the loaf is cooked, remove it from the tin and allow it to cool in the warm (switched off) oven with the door open.