Halve the avocados and remove the stones. Peel and discard the skin. Roughly chop the flesh. Transfer to a bowl and, using a fork, mash with the lemon juice.
Add the remaining ingredients, except for the coriander, and blend the mixture until smooth. Cover with a layer of cling film pressed lightly on the surface of the dip. Chill until needed.
Garnish with the chopped coriander just before serving.