With machine running, drop garlic through feed tube of processor and chop finely. Add mayonnaise and lemon juice. With machine running, drizzle in oil in thin stream, blending until smooth.
Transfer to small bowl. Whisk in za'atar and season with salt and pepper. Let stand at least 30 minutes to allow flavors to develop.
Do Ahead Can be made 1 day ahead. Cover and chill. Bring to room temperature before using.
Makes about 1 1/3 cups (10 two tablespoon servings)
Za'atar is a Middle Eastern spice mix that includes sesame seeds, sumac, dried thyme, and dried marjoram. It's available at specialty foods stores and Middle Eastern markets.
Please Note: Nutritional values listed may vary from final results depending on actual measurements and brands used to prepare the recipe.
Exchanges: 0 Vegetable; 0 Fruit; 2 1/2 Fat.