Tami Isaacs of Karma Bread says:
1. Get your hands in the dough and don’t use a mixer. You learn through your fingertips.
2. It will be sticky, but never add flour to the mixture ! Smear a little oil in the kitchen top before kneading to stop it sticking and keep scraping up the dough with a dough scraper while you knead.
3. Make sure you knead for at least 10 minutes. Drop your shoulders and really stretch that dough — pushing it away with your palms and pulling it back with your fingertips. Don’t just wiggle it about!
4. It must rise by at least 50% before you shape it and will carry on growing as you shape it.
5. Make sure you weigh the dough so you can ensure the strands are equal sizes.
6. Shaping the strands is vital for a good looking challah. Form the strands by first rolling out a flat strip and then pulling the long sides up together so the surface of the strand is taut in the top. Then roll into even sausages with tapered ends.
7. A steamy environment is best for proving. Achieve this by placing a cup of boiling water on the baking sheet and carefully placing the tray in a black bin liner, like a tent.
8. The loaf is ready to bake when it looks puffy and is about a third bigger.
9. Glaze carefully, into every crevice — try not to stab your dough!
10. Bake in the lower third of the oven as the crust can brown quickly and will not indicate whether the rest of the loaf is ready. Do not open the oven for at least 12 minutes. If, when you check, the crust is looking dark, cover it with foil to stop it burning.
Your challah will be baked when the underneath is a rich, golden brown.
Karma Bread, in Hampstead's South End Green, NW3 has reopened and is open for takeaway trade only Wednesday to Sunday 8.30am – 4pm.