Preparation

1. Boil the potato with its skin in lightly salted boiled water. Wrap the pumpkin in a sheet of aluminium foil and bake in a hot oven (180°C) for 20-25 minutes until the flesh is tender when pierced with a toothpick. Take the pumpkin out of the oven, remove the skin and seeds and cut it into pieces.

2. Combine the onion slices, a sprig of rosemary and 5 tbsp of olive oil in a heavy small saucepan. Cook over a low flame, without frying, to delicately amalgamate the flavours. Filter the oil through a strainer and set aside.

3. Peel the potato, cut it into cubes and place it in the beaker of an immersion blender with the pieces of pumpkin. Blend the mixture, gradually adding a drizzle of the aromatized oil and, if necessary, a little hot vegetable stock: the end result should be a thick cream.

4. Season with salt and spoon dollops of the cream onto individual dishes. Top with the Rio Mare Mackerel Fillets in Olive Oil and then garnish with the sprigs of fresh rosemary and a few grains of pink pepper.