The traditional sauce served on Greek gyros is tzatziki sauce, which is made from yogurt, cucumbers, dill and spices. Tzatziki is served with meats, on gyros or as a dip for vegetables and pita.
The key to a good, thick tzatziki is to drain the yogurt and cucumber well. Start with one English cucumber. Remove the seeds and chop finely, grate or shred. Squeeze the juice out of the cucumber pieces before adding to a bowl. You can do this by squeezing it in your hands or by using a cheesecloth to drain the cucumber. Add one cup of plain Greek yogurt; whole milk yogurt provides for the thickest consistency, but if you use lower fat yogurt, drain the yogurt of excess liquid through the use of cheesecloth.
Stir two cloves of finely minced garlic into the mixture along with 1 teaspoon of lemon zest and 1 tablespoon of fresh lemon juice. Chop 2 tablespoons of fresh dill, and add to the bowl. Season with salt and pepper to taste. After combining all the ingredients, chill the dip. This recipe yields 1 1/2 cups of dip and takes about 15 minutes to prepare.
This tzatziki sauce complements chicken, beef or lamb gyros nicely.