Green Bean Salad with Mushrooms and Mustard Dressing

Rinse the mushrooms, wipe with a paper towel and cut into small slices.

Rinse the tomatoes into quarters, remove the seeds and dice the flesh into small pieces. Rinse, trim and cut scallions into thin rings. In a pan, heat the oil, saute the scallion and add the mustard seed. Sauté briefly, deglaze with the vinegar and the broth, season with salt and pepper to taste and remove from heat.