For the steak tartare:
1. Prepare two small mixing bowls of similar size - one to mix the steak and one bowl to hold ice water. Have one mixing bowl filled with half ice and half water to make a proper ice bath. Put the empty mixing bowl on the ice bath.
2. Brunoise tenderloin, put it in the mixing bowl and coat it with extra virgin olive oil. Season to taste with salt and black pepper. Place a 1.75-inch diameter ring mould/cutter into the serving bowl and fill it with the seasoned tenderloin. While filling the mould, gently press the meat down to make a firm and even base. Just like a hockey puck.
3. Sprinkle finely-cut chives on top of the meat. Now take the mould out.
4. Quenelle the caviar and place it on top of the tartare.