Make an ordinary omelette, and before serving pour this mixture into it: - Take two or three tomatoes and cut them into pieces; slice an onion very thin, melt a tablespoonful of butter into a saucepan and place the onion in it. Cook them, but do not allow to color; add pepper, salt, and the pieces of tomato. Stir all together for ten minutes, take out the mixture, pass it through a sieve, and return to the pan; thoroughly reheat, and serve.