Start by bringing a pot of water to the boil. Have a slotted spoon close by.
Pour the oil into a blender jug followed by the hazelnuts, garlic, cheese, basil, salt, pepper, lemon zest, lemon juice.
Place the spinach in the boiling water for 30 to 60 seconds, until it goes bright green.
Transfer it from the water straight to the blender, along with 60ml of the blanching water.
Blend all ingredients to a bright green, smooth sauce. It should resemble thick double cream. You can adjust the consistency with a little extra blanching water if needed.
Season with salt and pepper to taste.
If cooking with gnocchi, add your gnocchi to the pan with a splash of the blanching water. Cook the starch out for a few minutes then add your sauce. Cook the gnocci with the sauce for 3 minutes to mantecare it. Top with more grated cheese and oil and serve.
