Mix the prawn marinade, adding salt and pepper to taste, and marinate the prawns for 1 hour in a bowl.
Place the olives on a baking sheet with baking paper, pat dry with a paper towel and place in the oven at 150ºC for 30 minutes. Remove, cool, and crush to a powder.
Cover the whole beets in aluminum foil and bake for 45 minutes at 180ºC until tender, then peel and blend to a smooth purée. Strain through a fine colander and bring the liquid to a simmer in a small saucepan. Once bubbling add the slurry and stir continuously over a low heat until it starts to thicken. Remove from the heat, let it cool, and reserve for plating.
Peel and cut the potato into flat ovals, then place the slices in a pan with enough olive oil to cover them completely. Add a pinch of salt to taste and a sprig of thyme and cook over a low heat for 45 minutes until the potatoes are crisp and tender.
Blend the mango to a purée. Simmer with the remaining ingredients over a low heat for 10 minutes. Cool and reserve for plating.
Mash the avocado well with a fork. Add the lemon juice, cilantro, and salt to taste. Mix well and set aside.
Finally, sauté the marinated prawns in olive oil in a hot pan on both sides until cooked. Serve as shown.
