To spread the bread, prepare the cheese and onion mass. Cut half of the onion into thin half-rings, brown in a non-stick frying pan with a pinch of sugar for caramelization. Grate the cheese on a fine grater, mix with the caramelized onion and mayonnaise sauce. You can add one crushed garlic clove for a more spicy snack.
Beat the chicken egg with a whisk until it forms a foam and fry in the same pan where the onion was previously browned, over low heat until tender.
Transfer to a plate, grease with fish roe, roll into a roll and cut diagonally into several small pieces.
Spread the bread with cheese and onion mass, put the lettuce leaves on top.
Put three egg and fish rolls on each loaf, decorate with rings of olives, sprinkle with flax seeds and sesame seeds. Bon Appetit!