Halve the chilli pepper lengthwise, remove seeds and chop finely. Wash, quarter, seed and finely dice the tomatoes. Peel garlic clove and chop finely. Wash coriander, shake dry, pluck leaves and chop finely.
Halve the avocado, remove the core, remove the flesh from the skin and crush finely with a fork. Mix whole milk yoghurt, avocado, tomatoes, garlic, coriander, juice from 1⁄2 lemon and chili.
Season vigorously with salt and pepper.