dijon green beans

1 1/2 lbs fresh green beans trimmed
3 tbsp red wine vinegar
3 tbsp olive oil
3 tsp dijon mustard
1 cup grape tomatoes, halved
1/2 small onion sliced
2 tbsp grated parmesan cheese
salt & pepper to taste

-place beans in large saucepan, cover with water and bring to a boil
-cook uncovered about 8-10 minutes
-in another bowl whisk vinegar, oil, mustard with salt & pepper.
-drain beans place in a serving bowl
--add tomato & onion
-drizzle with dressing, toss to coat
-sprinke with cheese-completely optional personally I opt out in this case