-Sliced cucumber for -garnish Soak gelatin in cold water for 2 minutes. Add boiling water and stir to dissolve gelatin. Chill until it becomes the consistency of egg white. Combine potatoes, onion, ham, cheese and egg. In a separate bowl mix vinegar, pepper, celery seed, mayonnaise, mustard and yogurt. Add to potato mixture and toss to coat well. Beat gelatin mixture until fluffy. Combine with potato mixture and pour into 2-3 cup mold or bowl. Chill to set. Unmold and garnish with sliced cucumber on lettuce leaves. Serving suggestion: Terrific picnic item. Take along a few bread sticks and a raw vegetable for munching. From the files of Al Rice, North Pole Alaska.