Wipe the red and green bell peppers.

Slice off the tops of the peppers and remove the pith and seeds.

Heat the oil in a pan.

Fry the chopped onions for 8 to 10 minutes, until golden.

Add the sliced brazil nuts and buckwheat groats to the pan.

Fry for a further 5 minutes, stirring occasionally.

Stir in the finely chopped mushrooms, sweetcorn, chopped parsley, chopped rosemary, 1/4 teaspoon salt, and pepper to taste.

Pile the mixture into the prepared bell pepper shells.

Replace the tops of the peppers.

Stand the stuffed peppers in a closely fitting pan.

Pour in the tomato juice and water.

Bring the liquid to a boil, then cover the pan and simmer for 55 to 60 minutes.

Carefully lift the peppers out of the cooking liquid and keep warm in a serving dish.

In a small bowl, blend the cornstarch with 2 tablespoons of tomato stock (from the cooking liquid).

Add the cornstarch mixture to the pot with the remaining cooking liquid and 1/8 teaspoon salt.

Simmer the sauce for 2 to 3 minutes, stirring constantly, until thickened.

Serve the sauce around the stuffed bell peppers.