Chop the garlic and chilli (if using), until you have a rough paste. Heat the oil in a large, deep frying pan, add the garlic and chilli and fry very briefly. Add the onions, peppers and salt. Stir once, cover, lower the heat and sweat for 10-15 minutes, or until it just starts to catch a little.
Meanwhile, drain the tomatoes and squish them to remove excess juice. Add the pulp and Vinegar to the pan, reduce the heat to low and cook for about 45 minutes, stirring occasionally. The peppers must be soft enough to break with a spoon, and the juices should be reduced, dark and glossy. Season to taste.
Preheat the oven to 200°C/fan180°C/gas 6. Mix the spinach through the pepper mix. Divide the vegetables between dishes, make a dip in each and break in an egg. Bake for 8-10 minutes, until the egg is just setting. Leave the yolk soft as it will enrich the peppers when it breaks. Garnish with herbs.