Recipe by Ard Bia at Nimmos as part of a mezze spread with two or three other dips  

Method 

Combine the chilli, garlic and vinegar in a food processor and blend until smooth.
Add the feta and pulse until fully mixed through, taking care not to over-blend as the feta will become very watery.
Check consistency and add a little milk to adjust.
Aim for a moist thin dip rather than a thick purée.
You could add a touch more vinegar at the end to adjust taste.