- For the sauce, put the olive oil, onion, lemon juice, olives, capers and parsley into Braun’s MQ 30 chopper accessory. Attach to a suitable hand blender and pulse until they are finely minced but not smooth.
- Bring the orange juice to the boil and reduce to thicken, stirring occasionally with a wooden spoon. Add the reduced orange juice to the chopper accessory and blend for only a few seconds. Make sure you do not overwork the mixture. Season to taste.
- Place a frying pan or griddle pan over medium-high heat and add 2 tablespoons of olive oil. Season the tuna generously with salt and pepper. Lay the tuna in the hot oil and sear for 1 minute on each side to form a slight crust.
- Serve with the orange, olive and caper sauce and garnish with orange segments and salad leaves