Watch how it’s made
Every step in 1:23 — from the ingredients to the finished dish.
Black beans are the highest-fiber bean in common use. A cup carries around 15 grams of it, which is roughly half a day’s target from a single ingredient, and considerably more than chickpeas or cannellini.
They also carry the most resistant starch of the three, which is the portion that passes to the large intestine undigested and behaves more like fiber than like carbohydrate. This is the vegetarian lunch on the site that leaves people fullest.
The cold-then-reheated effect
Resistant starch increases when cooked starch is cooled. Beans cooked and then refrigerated form more of it than beans eaten straight from the pan, and reheating does not undo most of the change.
That makes this a rare dish that is arguably better as leftovers than fresh, and it is worth cooking the batch a day ahead if you can plan that far.
Char the peppers, do not soften them
Fajita peppers should have blackened edges and still have some structure. Cooked gently until soft they go sweet and limp and taste of nothing in particular.
Get the pan properly hot before anything goes in, use a wide one, and resist stirring for the first two minutes. The black bits are the flavour.
Do not rinse the beans dry
Rinse them to remove the tinned liquid and its sodium, but leave them slightly damp when they go into the pan. A little moisture helps them take on the spices instead of just sitting alongside them.
Add them for the last three minutes only. Beans cooked long in a hot pan split and turn floury.
Lime at the end, always
Beans and charred peppers are both deep, savoury and slightly sweet, and the bowl tastes heavy without acid to cut it.
Squeeze it over off the heat. Lime cooked into the pan loses its brightness within a minute and just leaves sourness behind.
What this is not
There are two fajita recipes here now and they are different dishes. The tofu one is oven-roasted and served in lettuce leaves as wraps. This is a bowl, built on beans, cooked in a pan, and eaten with a fork.
If you want it as wraps, lettuce leaves work the same way. Two corn tortillas would add about 24 grams of carbohydrate, taking the meal to roughly 62, which is a real change rather than a detail.