First, pour the lukewarm water into a big mixing bowl, add the extra teaspoon of caster sugar and then carefully dissolve the yeast into the water.
Once bubbles start to appear on the surface of the water, pour in about a third of the flour, followed by the two eggs, the rest of the caster sugar, the salt and the oil.
Get your hands into the dough and combine the mixture, adding flour little by little as you go, until you get a big ball of dough. You will know when the dough is ready to knead because it shouldn’t stick to your hands any more. You may not need all the flour to get to this point, so just use what your own dough mixture needs.
Sprinkle a clean work surface with flour, tip your dough out onto it and knead for five to 10 minutes, adding a bit of flour if it gets too sticky again. Drizzle a little bit of leftover sunflower oil around the big mixing bowl.
Place the ball of kneaded dough back inside and cover with cling film. Leave the dough to rise for about an hour and a half or until it has doubled in size.
Once the dough has risen, give it a little punch to knock the air back out of it.
Place it back on the floured work surface and knead it a little bit, with a bit of flour if needed, so that it’s ready to shape. Use a rolling pin to roll the dough out into a thin, flat rectangle, and then cut long, thin strips of dough with a knife and braid the dough using three strands of dough at a time.
Make sure to hide a key wrapped in foil inside one of the plaits of dough. Shape the long plaits into a key shape (as shown in the photo).
Once you are happy with the shape, cover it with a clean tea towel or cling film and let it rise again for half an hour to one hour. Towards the end of this time, pre-heat your oven to 180 degrees Celsius and prepare the egg wash. Spread the egg wash generously over the challah with a pastry brush.
Decorate the challah with vegetables and herbs like a garden on top of the challah in a pretty design (as shown in the photo).
Bake the challah for 25-30 minutes at the bottom of the oven. You may need to cover the challah in foil at around 20 minutes if you feel it is getting a bit too brown and crispy!