1 tablespoon of lemon juice, about 1/4 of the lemon
salt to taste
tons of freshly cracked black pepper, this is an important flavor component of tzatziki
Start by mixing the yeast and sugar with the tepid water.
Whisk the mixture, and let it sit for 5 minutes. In the meantime, whisk 2 cups of the flour and the salt in a separate bowl.
Add the yeast and water mixture to the flour along with the olive oil, and mix until a dough begins to form.
Sprinkle more flour onto the counter top and begin to knead, adding flour as you go until the texture of the dough becomes smooth, slightly tacky, and plastic. Let the dough rest covered for 20 minutes.
Preheat the oven to 500F with a baking stone (if you don't have a baking stone, turn a cookie sheet upside down) on the center rack.
Cut the dough into 12 pieces and roll each piece out to about 4-5 inches in diameter.
Place the flattened pita onto a floured transferring board and slide onto the baking stone. The pita will puff up and get brown. They should be done after just 6 minutes.
Cook the steak however way you want. Let it rest for 10 minutes before slicing.
Wash and peel the cucumbers, onion, and garlic. With a simple box grater, grate all three of them using the finest setting.
In the same bowl, add the yogurt (some people use yogurt + sour cream for a richer, creamier sauce), the lemon zest and juice, and season with salt and pepper.
Refrigerate until serving.
Assemble and serve with extra tzatziki on the side.