Grate the 0.5 pepino inglés mediano rallado y exprimido seco on the large holes of a Grater. Gather the grated 0.5 pepino inglés mediano rallado y exprimido seco in a clean Kitchen Shears towel or cheesecloth and squeeze out as much liquid as possible — this is key to a thick tzatziki, not a watery one.

In a Mixing Bowl, combine the 1 taza de yogur griego natural de grasa completa, squeezed 0.5 pepino inglés mediano rallado y exprimido seco, minced 6 dientes de ajo pelados, 1 cucharada de aceite de oliva virgen extra, 1 cucharada de jugo de limón fresco, 1 cucharada de eneldo fresco picado finamente, and 1.5 cucharadita de sal kosher. Stir well, taste, and adjust seasoning. Cover and refrigerate for at least 20 minutes (or up to 2 days) to let the flavors meld.

Preheat your Oven to 325°F. Place the roughly chopped 1 cebolla amarilla mediana picada toscamente and 6 dientes de ajo pelados cloves in a Food Processor and process until very finely minced, almost a paste, about 30–45 seconds. Transfer the onion-garlic mixture to a clean Kitchen Shears towel and squeeze out as much liquid as you can — this prevents a soggy loaf.

Add the drained onion-garlic mixture back to the Food Processor along with the 1 lb cordero molido, 1 lb carne de res molida proporción de grasa 80/20, 2 cucharaditas de orégano seco, 1 cucharadita de romero seco, 1 cucharadita de comino molido, 1 cucharadita de pimentón dulce, 0.5 cucharadita de canela molida, 1.5 cucharadita de sal kosher, and 1.5 cucharadita de sal kosher. Process for 60–90 seconds until the mixture becomes a very smooth, paste-like consistency. This is important — it gives gyro meat its characteristic dense, even texture rather than a crumbly meatloaf texture.

Transfer the meat mixture onto a large sheet of Plastic Wrap. Shape it into a tight log or oval loaf about 8–9 inches long and 4 inches wide. Wrap tightly in the Plastic Wrap and use your hands to compact and smooth it further. Unwrap and place it in a Loaf Pan, pressing it in firmly with no air gaps.

Bake at 325°F for 55–60 minutes, until the internal temperature reads 165°F on an Meat Thermometer. The loaf will have released some fat and juices — that's normal.

Remove the loaf from the Loaf Pan and place it on a Cutting Board. Place another Cutting Board or heavy pan on top and weigh it down for 5–10 minutes — this compresses the loaf for cleaner, thinner slices (mimicking the density of spit-roasted gyro meat).

Switch your Oven to broil on high. Slice the pressed loaf into thin strips, about ¼-inch thick. Spread the slices in a single layer on a Aluminum Foil-lined Baking Sheet. Broil 4–5 inches from the heat for 2–3 minutes, until the edges are browned and slightly crispy. Watch closely — they can go from golden to burnt quickly.

Warm the 6 pan pita completo calentado directly over a gas flame for 30 seconds per side, in a dry Skillet over medium heat, or wrapped in a damp paper towel in the Microwave for 20 seconds.

To assemble each gyro: spread a generous spoonful of tzatziki down the center of a warm 6 pan pita completo calentado. Layer on a handful of gyro meat slices, then top with sliced 2 tomates roma medianos cortados en rodajas finas, 0.5 cebolla roja mediana cortada en rodajas finas, 0.5 pepino inglés mediano rallado y exprimido seco, and crumbled 3 oz queso feta desmenuzado if using. Fold the 6 pan pita completo calentado around the filling and serve immediately.