1 (3 oz.) pkg. lemon jello
1 c. boiling water
1 pkg. Knox unflavored gelatin
1 tbsp. cold water
1 tbsp. vinegar
1 c. plain yogurt
1/4 c. horseradish
1 tsp. grated onion
Tomato slices, 1/3 inch
Dash black pepper

Soften Knox gelatin in cold water. Mix with jello, boiling water and vinegar. Chill until syrupy. Add yogurt, horseradish, onion and pepper. Chill until set. Unmold on tomato slices.