Preheat the oven to 220ºC. Finely chop the garlic and the red pepper. Finely chop the shallot. Remove any hard stalks from the spinach and roughly chop the leaves.
Mix the shrimps with 50 ml of olive oil, red pepper and half the garlic. Put the prawns on the baking tray and grill in the preheated oven in 10 minutes.
Heat the mashed potato according to the instructions. Heat the remaining 25 ml of olive oil in a frying pan. Fry the shallot with the rest of the garlic for 2 minutes.
Mix the spinach and the fried onion and garlic with the mash. Add salt and pepper to taste.
Put the mash in the bowls and divide the grilled shrimps and the walnuts over the bowls.
Tip: marinate the shrimps with red pepper, garlic and olive oil for a few hours for an extra delicious flavor