1 tablespoon butter
2 green onions, chopped
1-1/2 cups (6 ounces) shredded Muenster cheese
4 ounces cream cheese, cubed
2 tablespoons ketchup
2 teaspoons Dijon mustard
1/4 teaspoon pepper
1/2 pound cooked corned beef, chopped
1 cup sauerkraut, rinsed and well drained
Place butter in a small microwave-safe bowl and microwave on high for 20 seconds or until melted. Add onions; cover and cook 1 minute longer.
Stir in the cheeses, ketchup, mustard and pepper. Cover and cook on high for 1 minute; stir. Cook 45 seconds longer. Stir in beef.
Place sauerkraut in a microwave-safe 1-qt. dish; top with beef mixture. Cover and microwave on high for 2-3 minutes or until heated through. Serve with crackers.