Line a fine mesh sieve with cheesecloth and spoon in the Greek yogurt. Leave for an hour to strain.

Next, prepare the cucumber by slicing it in half across the middle, then dividing each half into quarters. Cut out the seeds from the center and discard them, then finely chop the cucumber. You could also grate it if you wanted a finer texture to the finished dip. Place the cucumber into a second sieve, salt, and leave for an hour.

Discard any liquid that has drained from the yogurt and cucumber, then mix in a bowl together with the garlic, lemon juice, and dill. Stir well and test for seasoning, adding salt and black pepper as necessary.

Cover and store in the fridge overnight.

Pour off any excess liquid and transfer the tzatziki to a serving bowl. Store in the fridge until required.