Clean your peppers and place them on a baking sheet or baking dish.
After about ten minutes, check the pepper to see that it is starting to darken and cave in. Using tongs, turn it a quarter or third turn, depending on the shape of your pepper.
Keep doing this until the whole pepper is darkened and caved in, about 30 minutes.
When it is done, place it in a heatproof bowl and cover with a lid or plastic wrap and let cool.
Peel and discard the skin, open the pepper and remove the stem, seeds, and any remaining bits of the ribs (but most of that will have disappeared).
Leave whole or cut however you need for your intended use
Store them topped with a little olive oil in a glass container in the fridge, freeze in portions, or properly can them.