Cut the beetroot into small pieces and pat dry. Place in a container with the soy sauce and balsamic vinegar and refrigerate to marinate.
80 g beetroot, 1 tablespoon soy sauce or tamari, 1 tablespoon balsamic vinegar
Remove the herring's tail and feel with your fingers to check that no bones are sticking out. Cut the herring into pieces.
1 lightly salted new-season herring
Cut the spring onion into thin half-rings and mix with the herring. Cut two neat whole rings for garnish.
0.5 spring onion
Cut the lemon into very small pieces and gently pat dry.
20 g preserved lemon
Drain the beetroot, collecting the marinade in a container to use as a sauce later. Mix the beetroot pieces with the lemon.
Stir the mayonnaise into the marinade.
1 teaspoon mayonnaise
Assemble on the plate. First place the beetroot in the plating ring and press down. Then spread the herring on top and press down.
Carefully lift off the ring. If necessary, press down gently on the tartare as you lift, but not too hard, or the little tower will collapse. Garnish with the reserved spring onion.
Just before serving, dot the sauce around the little tower.
Notes
You can line the ring with a strip of acetate before assembling. Once filled, remove the ring, then unwrap the acetate.Equipment: round cutter / plating ring, small bowls, spoon, knife, optional: acetate film.