Bake chicken patties according to package directions. Meanwhile, in a 10-inch skillet cook kohlrabi, mushrooms, onion, celery, rosemary, and 1/2 teaspoon salt in hot oil over medium heat 10 minutes. Stir in tomato and garlic. Simmer, uncovered, 5 minutes more.
Toast rolls, if desired. Spread bottom of buns with mayonnaise or salad dressing; place lettuce and chicken patty on each. Spoon sauce over. Add bun top. Makes 4 servings.