1.Heat oil in 28cm frying pan, cook potato, onion and beans, covered, stirring occasionally, until vegetables soften.
2.Whisk eggs lightly in large bowl, whisk in pesto and chopped basil. Pour egg mixture over vegetables, sprinkle with cheese. Cook frittata, uncovered, over low heat until almost set.
3.Meanwhile, preheat grill.
4.Place pan under grill (shielding handle with foil, if necessary) until cheese melts. Remove from heat, stand 10 minutes.