Heat your oven to 200°C/Fan 180°C/Gas 6. Scrub and trim the carrots. Slice them into batons as thick as your little finger. Spread them out on a baking tray. Drizzle with 2 tsp oil. Season. Toss to coat. Roast for 25 mins till tender and a little charred.
If you have a gas hob, turn on a large burner and place the whole pepper directly on the flame. Char over the flame, turning every so often, for 10 mins till the pepper is charred all over. Alternatively, char the pepper under the grill.
Set the pepper aside to cool. Roughly chop the chilli, flicking out the seeds for a milder flavour. Peel and roughly chop the garlic. Pop them both in a food processor (see our tip if you don’t have one).
Measure 1 tsp of the cumin seeds into a dry frying pan. Toast over a medium heat for 1-2 mins till they start to pop and smell nutty. Chuck them in the food processor with a pinch of cayenne pepper (it’s spicy, so add a small pinch to start).
Peel the charred skin off the pepper. Halve, deseed and roughly chop the pepper. Add it to the food processor with 2 tbsp of the vinegar. Season and blitz to make a rough mojo rojo sauce. Taste and add more seasoning or cayenne if it needs it.
Line a baking tray with foil. Brush with 1 tsp oil. Lay the fish on it. Bake on the shelf below the carrots for 5-8 mins till the fish is opaque and flakes easily when pressed with a fork.
While the sole bakes, trim the woody ends off the French beans. Pop the beans in a pan. Cover with boiling water and simmer for 3-4 mins till just tender. Drain well. Serve the lemon sole with the beans, roasted carrots and mojo rojo.