1. Drain 1 can of tuna. Chop 4 anchovy fillets, cut 4 into strips and set aside. Rinse capers, 2 tsp whole and set aside, chop the rest. Chop parsley finely medium fine. Boil eggs until hard, rinse and peel.
Place drained tuna in a large enough bowl. Add the tuna from the second can with oil. Add the juice of one lemon as well. Blend everything with a blender until the consistency is creamy. Add the mustard and mascarpone with the blender. 3.
Fold in minced parsley, anchovy fillets, capers, green pepper and lemon zest with a wooden spoon. Put the tuna mousse in the refrigerator for 10-15 min.
In the meantime, cut the eggs into six. Cut pita bread into slices and toast.
To serve, dip ice cream scoop (or tablespoon) in cold water, portion the mousse with it and arrange on a platter. Decorate with the remaining anchovy fillets and capers, eggs and celery stalks. Serve the toasted pita bread with the tuna mousse.