Using a mortar and pestle, coarsely crush the pistachios and all the other ingredients up to and including the cumin. Heat a non-stick frying pan, toast the spice mix for approx. 1 min. without allowing it to take on any colour, season with salt.
Mix the fennel with the oil, salt and pepper, transfer to a baking tray lined with baking paper.
Bake for approx. 40 mins. in the centre of an oven preheated to 200°C.
Season the tuna. Heat the oil in a non-stick frying pan. Fry the tuna for approx. 1 min. on each side, toss immediately in the spice mix.
Plate up the fennel, top with the burrata, drizzle with lime juice and garnish with basil. Serve the salad with the tuna.