Chipotle Artichokes with Feta and Avocado

Chipotles are small, hot Mexican chillies with an intense smokiness that works well here with the subtle flavours of artichoke and avocado. Remember to prepare the avocado just before cooking to prevent it from browning, but the artichokes can be prepared a day or so in advance if kept in water to which a spot of lemon juice or vinegar has been added (you could also poach them in advance). Should you want to avoid the job of preparing them yourself, peeled frozen artichoke hearts are