The colour comes from a spice mix called berbere. It is made from chillies, garlic, ginger, basil, cinnamon and many other spices, all ground together to a deep red-orange powder. Almost every Ethiopian family has their own berbere recipe, often passed down from grandma.
To make doro wat, the cook starts by slowly browning a huge pile of finely chopped onions in butter for an hour or more, until they are sweet and soft. Then they add the berbere, the chicken, and water, and let it bubble gently for hours until the stew is thick and rich.
A boiled egg goes into the pot near the end. By the time the stew is ready, the egg has soaked up the warm red sauce and turned a deep colour itself. There is usually one egg per person at the table, and being given the egg is considered a small honour.
Doro wat is the meal for special occasions. Christmas, Easter, weddings, Eid, the Ethiopian new year - whenever a family gathers, there is doro wat. It takes hours to make. That is part of the point: the long slow cooking is how you say 'we are happy you are here'.