Peel the layers away from the fennel and finely slice the fennel.
Place the sliced fennel in one layer onto a solid baking tray and season with salt, pepper and a drizzle of evoo.
Place the salmon fillet on top of the fennel and season the salmon with lemon zest, pepper and salt, drizzle over a little evoo and place the salmon into a pre-heated oven combi setting 190 °C for 7-9 minutes.
While the salmon cooks place the garlic and cashew nuts into the bowl of a food processor and blitz until roughly chopped. Add the spinach leaves a little more lemon zest, salt, pepper and approx 20gm of evoo. Blitz again until you have a rough but even textured paste. Check the seasoning and set aside.
Once the salmon has baked remove it from the oven and place the roasted fennel on to a plate, place the salmon on top and a spoon full of pesto onto the salmon and serve.