Rub some oil around the inside of a 1kg/2lb loaf tin or insert a baking liner.
Put the flour, sugar, bicarbonate of soda, xanthan gum, vitamin C if used, and salt into a large bowl, stir to combine and sieve into a mixing bowl.
Measure the boiling water into a jug and add the cold water.
Add the yoghurt or lemon juice, if used, and stir to combine.
Pour this into the mixing bowl and stir everything together to make a soft, sticky dough.
Drizzle the oil over the sticky dough and using a spatula, turn the mixture a couple of times in the bowl to encourage the formation of a doughy mass.
Tip the doughy mass into the prepared tin and smooth the top.
Brush some oil over a piece of aluminium foil. With the oiled side down, cover the tin creating a dome so that the bread can rise during cooking.
Bake for 60 minutes.
Carefully remove the aluminium foil and bake for a further 10 minutes.
Turn the loaf out onto a wire rack. The bottom should sound hollow when tapped.
Cool completely before slicing.
1kg/2lb loaf tin, aluminium foil, sieve, large mixing bowl and jug
200°C, Fan 180°C, 400°F, Gas 6
60 minutes + 10 minutes
Delicious & really light! Made some Paleo/coeliac/other changes which I hope help: Buttermilk for yoghourt, 2 tsp Chia seeds instead of Xanthan gum, Baking powder (Gluten-free, use 3x amount) for Baking soda & Lemon juice. Icing sugar replaced with 2tbsp fine ground Coconut sugar (1 cup : 1tbsp Arrowroot pwdr in Nutribullet)