Basic Recipe

• True sour cream is cream that has been cultured, or soured, with lactic acid and it must contain at least 18 percent milk fat by weight. Aside from the sour cream, tzatziki also commonly includes cucumber, an oil -- usually olive -- and an acid, usually lemon juice, though vinegar can be used as well. The sauce is often flavored with garlic and fresh herbs, like dill.

Lightening Up

• Lighten up your gyro sauce recipe with low-fat or light sour cream, which is actually cultured half-and-half. Use it, cup for cup, the same way you would use yogurt or sour cream.

Fat-Free

• Mix a batch of fat-free gyro sauce using fat-free sour cream, which is actually made from cultured skim milk. Be aware that fat-free products contain additives, including gelatin, modified corn starch, agar gum and sodium citrate to compensate for the lack of dairy fat.

Vegan

• Make gyro sauce with vegan sour cream. Purchase vegan, tofu-based sour cream substitutes at a health food grocer, or make your own. You can also make a sour cream substitute using pureed cashews. The finished product won't taste exactly like traditional gyro sauce, but you'll have a creamy, cool dressing for a vegan meal.