Boil up about 1 litre of water in a high pot. Add vinegar essence. Beat the eggs one by one in a cup and let them glide one by one into the boiling water. Cook over low to medium heat for about 5 minutes.
Heat the sauce in a small pot. Wash, clean, quarter and seed the tomato. Cut the flesh into small cubes. Remove the eggs from the water with a skimmer and let them drip off on kitchen paper.
Halve the toasti and toast. Halve the slices of ham. Place 1/2 slice on each half of a toasti, place 2 poached eggs and some sauce on each slice. Sprinkle with tomato cubes and garnish with chervil and coarse pepper.