HEAT oven to 350°F.
BEAT eggs, milk, onions and herbs with whisk until well blended.
HEAT oil in 8-inch ovenproof skillet. Add egg mixture; cook, without stirring, 4 min. or just until set around edge. Top with tomatoes and Parmesan.
BAKE 20 min. or until centre is set. Let stand 5 min.