Finely chop the shallot and place in the food processor.
Squeeze the limes. Add half the lime juice and the chilli powder to the shallot.
Cut the avocados all the way around the stone. Twist the two halves apart. Spoon out the stone. Scoop the flesh out of the skin and slice into pieces. Cut 1 half avocado into small cubes for the garnish. Add the rest of the avocado and the parsley leaves to the shallots in the food processor. Sprinkle some lime juice onto the avocado cubes and season with salt and pepper.
Purée all the ingredients in the food processor. Gradually add the vegetable stock and sour cream.
Drizzle the rest of the lime juice over the shrimps. Season with pepper to taste and olive oil.
Pour the avocado soup into deep bowls and garnish with the prawns and avocado cubes.
Prefer to leave out the shrimps? Crumble some feta or crispy fried Parma ham over the soup.
Prefer vegan? Replace the sour cream with creamy oat fraîche and sprinkle with toasted pumpkin seeds.
