Mustard Seeds If you are like most people, the word "mustard" probably conjures up images of ballparks and barbeques. Yet, once you add mustard seeds to your spice cabinet, the word will take on a whole new meaning, as you will also relish the spicy, aromatic rustic taste and fragrance that mustard can add to your meals. Mustard seeds are from the mustard plant, which is a cruciferous vegetable related to broccoli, Brussels sprouts and cabbage. Yellow mustard seed is the traditional type sold in grocery stores, commonly used for pickling, canning and sausage making. Brown mustard seed is smaller and hotter, traditional for Asian and African cooking. In India, whole brown seeds are fried in oil until a popping sound is heard. This gives the seeds a nutty flavor, important in many vegetarian dishes.