Finely chop or grate the zucchini. Mix well the oat flakes, flour, eggs, 2 shallots or a medium-sized onion with a little garlic. If you want, you can also mix in 50 g Parmesan or hard cheese. Then season with the spices and herbs and leave to soak for about 20 minutes.
Fry the zucchini mixture on both sides in a spoonful of butter or oil.
For the tartar sauce, mix mayonnaise and yoghurt with the yolks of the hard-boiled eggs. Season to taste with mustard, salt, pepper, Tabasco and Worcestershire sauce. Chop the shallot, capers, gherkins and the remaining egg white from the hard-boiled eggs and stir in with the herbs.
Add the sauce to the zucchini buffers and serve with tomato slices.