Thinly slice the onion. Slice the pepper into rings. Roughly chop the tomatoes.
Heat a spoonful of vegetable oil in a frying pan, then gently sauté the onion and pepper for 5 minutes. Add the tomatoes (and chilli if used).
Cut the frankfurters into 1cm lengths, add these to the vegetables with a couple of pinches of paprika.
When the tomatoes have released their juices, pour in the beaten eggs, allowing the mix to spread out evenly.
Cook over low heat for about 10 minutes, until the egg sets. You can put a lid on for the top to cook through properly, or finish it off under the grill until the top is golden.
Serve with paprika (or chilli powder) sprinkled over it and with crusty bread on the side.