Marinade: Combine and mince the rosemary leaves, fennel and garlic. Add 50 ml olive oil and mix until blended.
Sprinkle tuna with Vegeta Delight vegetable stock powder, place in the marinade and let stand 10 minutes.
Heat up a frying pan and sear tuna steaks, ensuring they remain pink in the centre. Add some more of the remaining marinade.
On a plate arrange a bed of rocket leaves and corn, add blood orange, olives and drizzle with remaining olive oil and vinegar. Arrange tuna steaks over the top and drizzle with the marinade.
Perfectly cooked tuna steaks should be well seared on the outside, and pink and soft inside. Tuna dries out easily so make sure to keep it juicy and silken by adding tuna steaks to the moderately hot but not too hot olive oil and by flipping the steak only when the bottom side is seared.