Char and skin the peppers, and then seed and chop them. Cook the onion in the olive oil or butter, until soft.
Add the tomatoes, and continue cooking until you have a thick purée. Lightly beat the eggs. Lower the heat under the pan, and once the mixture is no longer boiling, stir in the eggs.
Season with salt and pepper, and cayenne or chilli powder, and continue stirring over a low heat until the eggs are cooked to a cream. They should not be lumpy but should have amalgamated with the purée and thickened it. Serve immediately with toast or fried bread.