Cut off the top quarter of the eggplant.
Scoop out pulp leaving shells about 1/2 in. thick.
Chop the pulp roughly.
Melt the butter in a frying pan.
Add the eggplant pulp, onion, sliced green pepper and garlic.
Cook until soft, then add the rice, tomato puree, salt and cayenne.
Fill eggplants shell with this mixture and bake in hot oven for 15 minutes.