Potato Salad with Mustard Greens

3 Tbs unseasoned rice vinegar
1 tsp finely chopped fresh thyme
2 Tbs olive oil
1 1/2 tsp Dijon mustard
2 lb red potatoes, peeled and diced
4 celery stalks, sliced 1/2 inch thick
1 bunch mustard greens, stems removed, leaves coarsely chopped

1) Whisk together vinegar and thyme in a small bowl. Whisk in oil and mustard, and season with salt and pepper, if desired. Marinate 20 minutes, tossing often.
2) Meanwhile, steam potatoes 13 to 14 minutes, or until tender. Transfer steamer rack to work surface and let potatoes cool for five minutes.
3) Toss potatoes with dressing in a wide, shallow bowl. Cool 10 minutes, or until dressing is absorbed, tossing occasionally.
4) Steam celery 6 minutes, or until only slight crunch remains. Cool briefly. Fold into potatoes. Fold in mustard greens. Season with salt and pepper, if desired.

Review: The mustard greens added an extra mustard punch to this dish. However, I apparently don't like that. I can see why it was picked for this dish, but the vague mustard taste just wasn't pleasing to me. I'd love to make this again, but double the dressing and substitute in collard greens.

Adapted from:
http://www.vegetariantimes.com/recipe/potato-salad-with-mustard-greens/