Tzatziki sauce is a garlic cucumber yogurt sauce, which can also be used at just a dip. He is how to make it.
Ingredients:
Greek Yogurt (regular yogurt is fine just let it sit overnight in cheesecloth to let drain some of the excess liquid out overnight)
Cucumber
Garlic
Olive oil (I use greek olive oil, which is thicker, greener, and has a more intense stronger flavor than most olive oils in the store)
Lemon
Fresh herb (I use thyme, others use dill, some just use parsley, some don't use anything)
Salt and white pepper ( I use black pepper because I don't have white pepper)
Peel and remove seeds from cucumber before finely dicing the cucumber and placing it in a strainer. Sprinkle with salt and set aside to allow some moisture to be removed from the cucumber.
With the garlic portion you can go two ways and each has it's own benefits. You can use roasted garlic or fresh. If I am making for just a dip I like to use roasted garlic because it is more mellow than using fresh garlic, but using it as a spread with lamb I like fresh garlic. To make the roasted garlic, cover garlic (whole or minced) with olive oil and keep over low heat to warm the oil and slowly extract the garlic flavor into the oil. You can keep the oil for other uses or use the oil in the tzatziki sauce, which is what I normally do.
With the cucumber and garlic ready add them both to the yogurt with the zest of a whole lemon, salt, pepper, and the fresh herbs if you choose. Once mixed, add some of the juice of the lemon to loosen the mixture up, taste and reseason if necessary. Allow the tzatziki to sit in fridge overnight to allow the flavors to fully develop before using. Enjoy!