01The sauce won't hold a well
Simmer uncovered before adding the eggs. Draw a spoon through the sauce: if a watery layer immediately runs into the gap, more liquid needs to evaporate. A thick sauce will briefly hold a shallow well. Stir and check the bottom of the pan as it cooks, rather than simply turning up the heat.
02The sauce is sticking or too thick
Reduce the heat and stir in water a tablespoon at a time. Don't add lots of liquid at once, only to have to cook it off again. Cook garlic and ground spices only briefly before adding the tomatoes. Spices that have already burnt and taste bitter will not become milder with longer cooking.
03Check the egg whites and yolks
A lid helps heat the tops of the eggs. Cook over a low heat, paying particular attention to the egg white right next to the yolk: it must not remain translucent or runny. For fully cooked eggs, let the yolks set too. Pregnant women, young children, older people and people with weakened immune systems should choose fully cooked eggs.
04More portions need more surface area
The basic recipe uses a pan of around 24 cm for four eggs. More eggs need extra surface area, not just a deeper layer of sauce. Use a wider pan or two pans. Ingredient quantities can be multiplied, but cooking times should not be scaled up automatically: judge them by the consistency and how thoroughly everything is cooked.
05Prepare the sauce ahead
Cook the base without the eggs, cool it quickly and refrigerate within 2 hours. Store in a sealed container at 4°C and use within 2 days. Before adding fresh eggs, reheat thoroughly until steaming. Only reheat the portion you need, and do not reheat leftovers repeatedly.
06Add the finishing touches
Add herbs and feta just before serving; take the feta into account when seasoning with salt. Serve bread separately so it doesn't get soggy in the sauce beforehand. Cook spinach and other vegetables with a high water content before adding the eggs, and reduce any excess liquid.