Roast fillet of cod with saffron potatoes and tomatoes

Preheat the oven to 110°C/gas mark 1/4

For the roasted tomatoes, cut in half lengthways and season. Drizzle with a little olive oil, place in the oven cut-side up and cook for about 6 hours until soft and concentrated

Trim the cod fillet into a neat, long, even piece. Lightly salt the fish, roll tightly in cling film and place in the fridge for 6 hours. Remove from the fridge, wash the salt off and re-roll in cling film. Cut into 4 equal pieces and set aside until required

For the tomato dressing, gently warm the oil with the garlic in a pan over a low heat, taking care not to burn the garlic

Meanwhile, place the tomatoes into a blender and blitz until they are broken down. Slowly pour the garlic-infused oil into the tomatoes as the blender is still going – it will emulsify. Once thick and smooth, remove from the blender and place into a container

For the saffron potatoes, trim each potato into a barrel shape or use a Parisian spoon (melon baller) to form small 2cm balls. Place in a pan of cold water with the garlic and a pinch of saffron and salt. Cook until soft, but ensure the potato balls are firm enough to hold their shape. Leave to cool immediately in ice cold water and set aside

To cook the vegetables, place the white asparagus in salted boiling water for 2-3 minutes until tender

Remove and refresh in ice cold water. Repeat this process with the baby fennel, then gently pull apart each layer, trimming the top and tail to neaten up

Remove the cod from the cling film and cut into 4 even fillets. Add a little oil to a non-stick pan and add the cod, skin-side down

Once there is some colour on the skin, turn the heat down to low and leave for 5 minutes. Turn the fish over and cook on the other side for a further 4-5 minutes until cooked through

Meanwhile, prepare the rest of the vegetables. In a warm pan, lightly wilt the spinach and season. Dry in a cloth so no excess juices leak onto the plate

Warm the potatoes and other vegetables in a warm pan with the butter, season and keep warm

With a pastry brush, lightly brush the softened butter over the plate and dust with the beetroot powder. Shake off any excess powder

Serve a small amount of spinach in the middle of each plate, then arrange the cod on top. Dress the plate with the tomatoes, vegetables and potatoes. Drizzle with the tomato dressing and serve immediately