Heat oil in a large frying pan, season prawns with salt, pepper and sumac, cook for approx 3 minutes.
Squeeze some lemon over the prawns and toss with chopped coriander.
For the tabouleh
Using a very sharp knife, slice the bunch of parsley (including stalks) as thinly as possible, starting at the top all the way down till the leaves stop from the stalks.
Repeat with the mint leaves, (the stalks are a little too woody to use).
Combine the tomatoes, onion, lentils, herbs and spices and season with salt. Dress with lemon juice and olive oil.
For the avocado cream
Place all the ingredients in a blender and blitz until smooth, season with salt and pepper.
To serve
Spoon the avocado cream into lettuce leaves and top with tabouleh, then prawns.