Prepare the meat as described in the recipe for beef filet. You can either take filet or any other piece of beef. Just cook it long enough, filet 2 hours, other pieces 3 hours. Let the meat cool down and put it in the fridge for at least 3 hours. Then slice it as thinly as possible.
For the tuna mayonnaise drain the oil from a tin and put the fish, the capers and the anchovies in a blender. If you don’t have capers and anchovies, never mind. The sauce tastes nice only with tuna, too. When these ingredients are finely chopped, mix them with the mayonnaise. To make the sauce easier to spread, add the milk in the end. Be careful not to add too much milk.
To finish your dish, choose a nice bowl with a lid. Start with one layer of meat slices, cover them with tuna mayonnaise and continue layering the meat and the mayonnaise until you have used everything up. You should finish with a smooth layer of tuna mayonnaise which you can decorate with some capers. Now cover it with the lid and keep it in the fridge for some hours. Remember to check your dish after a couple of hours to make sure everything is well with your vittel tonnee.