Broccoli and Cauliflower Gratin

This recipe is adapted from The Cook's Encyclopedia of Vegetarian Cooking.

9 ounces cauliflower florets
9 ounces broccoli florets
1 cup plain yogurt
1 cup grated cheddar cheese
1 teaspoon prepared whole-grain mustard
1/4 cup Italian Panko breadcrumbs

1. Cook the cauliflower and broccoli in light salted boiling water for 10-12 minutes or until tender. Drain well and place in an ovenproof dish
2. Mix the yogurt together with grated cheese and mustard.  Salt and pepper to taste.  Spoon over the vegetables.  Sprinkle with the breadcrumbs.
3. Preheat the broiler and broil until the crumbles and browned, about 3 minutes.