This is really a play on the classic confit d'ail, or preserved garlic (find that recipe here). It's a simple recipe that--especially in the case of these peppers--really packs a punch. What it boils down to (yes, the pun was intended) is that you slowly poach the vegetables in olive oil until soft as butter and lightly browned. You can store them in the oil (as was originally intended) as a for of preservation, or you can eat them straight away (as is often the case). You can also incorporate them and the oil into another recipe for a flavor boost. Anyhow, this is really easy to make. For a full description read this post.