For the dressing:
3 Tbsp ketchup
2 Tbsp mayonnaise (light or low-fat)
4 Tbsp nonfat Greek yogurt
3 Tbsp sweet pickle relish
1 tsp tomato paste
Kosher salt and black pepper, to taste
1 head iceberg lettuce (buy a firm one)
1-2 tsp minced red bell pepper, for garnish
In a bowl, whisk together all of the dressing ingredients. Refrigerate until ready to use (you can make this up to 1 week ahead).
Cut the iceberg lettuce into wedges, using approximately one-fourth of the head for each wedge.
Place the lettuce wedges on individual plates, and drizzle with some of the dressing. Garnish with red bell pepper.