Season the tuna slices with salt, pepper and a little oil, divide them into two vacuum cooking bags and seal.
Place the blade cover in the jug, place the bags containing the tuna and add as much water as needed to cover them completely.
Remove envelopes, 7 mins / 50 ° / anticlockwise / speed 1.
Insert the bags with the tuna, vacuum packed / 25 min./48°.
Remove the bags and transfer them to a container with water and ice to quickly lower the temperature.
For the zucchini cream
Put the water in the clean jug, place the basket and add the potatoes first, then the courgettes, close with the measuring cup and cook 20 min / Varoma / speed 1.
Carefully remove the Varoma and basket, empty the mixing bowl and put only the courgettes in it, 10 sec / speed 10.
Add potatoes, salt, milk, butter, 30 sec / speed 4.
Position the throttle, 20 sec / speed 3.
Remove the tuna from the bags and dry it with kitchen paper, sprinkle it with sesame seeds and roast it quickly over high heat in a non-stick pan containing a little oil.
Pour the courgette cream onto the plate, add the tuna and season with the teriyaki sauce.