Napa Green Bean Salad

(It's called "Napa" salad because I got the ingredients for the dressing on a trip to Napa).

1 1/2 lbs. green beans and yellow beans
Dressing:
1/4 cup extra virgin olive oil
2 T balsamic vinegar
2 T Dijon mustard (the grainier, the better)*

*I used this pink, large grain mustard. I had never seen pink mustard before. It has a nice, mellow flavor, without being spicy (at all) like some Dijon mustards can be.

Boil pot of salted water. Add green beans and yellow beans. Prepare a bowl of ice water. Once the beans are cooked (about 5 min), transfer the beans to the ice water (putting them in ice water stops them from cooking, which keeps them from being overcooked and mushy).

While the beans are cooking, whisk together the olive oil, vinegar, mustard, and salt and pepper (to taste). There's no need to stream in the olive oil because the mustard will hold the rest of the dressing together.

Mix the blanched green beans with the dressing, and enjoy!