For the tzatziki: Place the cucumber into a strainer or colander over a bowl and squeeze with your hands the shredded cucumber to release the liquid. When the liquid comes to a slow drip, set the strainer into a bowl and set the bowl in the refrigerator to continue to slowly drip for 30 minutes. Make sure the bottom of the strainer does not touch the bowl. (The purpose of straining the cucumber is important to retain the thick consistency of tzatziki sauce. You can either discard the cucumber liquid or reserve it to make a refreshing cucumber water drink.)
Empty the yogurt into a medium bowl. Add the strained cucumber along with the garlic, dill, vinegar and oil into the bowl and gently mix with a whisk. When all the ingredients are equally distributed, your tzatziki sauce is ready. Season with salt and pepper, if using. (Sauce can be prepared a day in advance and refrigerated.)
For the bifteki: In a medium bowl, add the ground beef, red onion and mint leaves. With your hands, work in all the ingredients until everything is equally distributed. Then add the crumbled cheese and mix, being careful not to overwork the mixture. You want the cheese to stay relatively chunky. Form into a loaf and cut into 6 equal pieces, about 5 ounces each. Form each piece into an oval-shaped meatball and then pat down to form an oval shaped patty. (Patties can be prepared a day in advance and refrigerated.)
For the sandwich: Cook each patty on a hot charcoal grill or broiler for 2 to 3 minutes on each side until desired temperature is reached. (I like this patty cooked to medium, unlike my burgers that I prefer on the rare side.)
Lightly toast the baguettes on the grill, if desired. Remove from the heat and then spread 1 tablespoon of tzatziki sauce on the top half of each baguette piece. When the patties are ready, remove from the heat and cut on a bias into 3 equal parts. Spread the cut pieces over the bottom half of the toasted baguette. Top the patty with sliced tomatoes and sliced red onions. Sprinkle some salt and pepper and Spanish smoked paprika, if using. Press both sides of the baguette together and enjoy.
Use yogurt with full fat content, don't deprive yourself of flavor by using 2-percent or fat-free yogurt. If Greek yogurt is not available, you can substitute with any yogurt providing that you strain it. To strain the yogurt follow these simple steps: Empty a 1 liter container of any plain, full fat yogurt into the center of some cheesecloth. Then place the 4 ends of the cloth together and twist. Keep twisting the ends so that you can squeeze the whey (liquid) out of the yogurt and into a bowl. Keep twisting and squeezing the yogurt until it comes to a slow drip. Knot the end of the twisted cheesecloth or tie it together with some twine. Place the cloth containing the yogurt in a strainer or a colander, and then place the strainer or colander over the bowl. Make sure it doesn't touch the bottom of the bowl so that the whey can continue to slowly drip. Now place the bowl in a refrigerator and allow it to drip for 3 to 4 hours. Remove from refrigerator and give it one more squeeze to strain out any stubborn liquid that may remain. Untie the cheesecloth and, with a spatula, place the desired amount of the now strained yogurt in a prep bowl. The strained yogurt should be at least as dense as sour cream. The remainder of the yogurt could be set aside for later use or just add some salt and herbs and you have homemade cream cheese. You can also reserve the whey to use for pickling (instead of vinegar), or for making anything from breads to beer.
This recipe was provided by a chef, restaurant or culinary professional. It has not been tested for home use.
Recipe courtesy of Evangelos Rounmeliotis and Pablo Garcia, owners, The Sparrow Tavern, Astoria, NY