Peel and roughly chop the beetroot then process in a juicer. Add the balsamic vinegar and olive oil to the juice. Season with salt and piment d'Espelette.
Peel and finely dice the shallots. Wash the baby spinach. Cut the foie gras into slices using a knife dipped in hot water.
Heat a frying pan, add a little olive oil and then sear the tuna steaks on both sides. Remove from the pan once the tuna is coloured on the outside but pink in the middle. Season with salt and piment d'Espelette.
Fry the foie gras in a hot pan and then season with salt and set aside.
Dress the spinach leaves with olive oil, sherry vinegar and the finely chopped shallots.
Place a handful of spinach leaves in the centre of deep dinner plates or soup bowls. Place the tuna on top of the spinach and top with a foie gras slice. Finish with the beetroot drizzle.
«You can prepare the tuna and the foie gras in advance and simply reheat in the oven before serving - though be careful not to overcook the fish!»