Heat a lightly oiled, ovenproof, small non-stick frying over a medium heat. Add sweet potato and cook, stirring, for 2-3 minutes, until heated through.
Stir in capsicum and spinach. Pour over eggs. Season with freshly ground pepper. Sprinkle with olives and 1 tablespoon parmesan. Cook for 2-3 minutes, until almost set. Meanwhile, preheat oven grill to medium-high.
Place pan under preheated grill. Cook for about 2 minutes or until omelette is set and top is lightly browned. Sprinkle with remaining parmesan. Slide onto a plate to serve.