Prepare the Chicken Marinade: In a large bowl, combine 125g (1/2 cup) of Greek yogurt, 60ml (1/4 cup) of lemon juice, 30ml (2 tbsp) of olive oil, 4 minced garlic cloves, 2 tbsp (6g) dried oregano, 1 tsp (3g) smoked paprika, 1.5 tsp (9g) salt, and 1 tsp (3g) black pepper. Whisk everything together until well combined.

Marinate the Chicken: Add the bite-sized chicken thigh pieces to the marinade. Toss thoroughly to ensure each piece is evenly coated. Cover the bowl with plastic wrap and refrigerate for at least 4 hours, or preferably overnight, to allow the flavors to meld and the chicken to tenderize.

Prepare the Tzatziki Sauce: Peel and finely grate or shred 1 medium cucumber (about 200g). Place the grated cucumber in a fine-mesh sieve set over a bowl and gently press to remove as much excess water as possible. This is a crucial step to prevent a watery tzatziki.

Combine Tzatziki Ingredients: In a separate bowl, combine the remaining 125g (1/2 cup) of Greek yogurt with the squeezed grated cucumber. Add 2 tbsp (6g) of chopped fresh dill, 1 tbsp (3g) of chopped fresh mint, 1 tbsp (15ml) of red wine vinegar, and 1/2 tsp (3g) of salt. Stir well to combine.

Chill the Tzatziki: Cover the tzatziki sauce and refrigerate for at least 30 minutes to allow the flavors to develop and thicken. This can be done while the chicken is marinating or while you prepare other components.

Prepare the Vegetables: Thinly slice 2 medium tomatoes and 1 small red onion. Chop 1/4 cup (15g) of fresh parsley. Set aside.

Grill the Chicken: Preheat your grill (outdoor or indoor grill pan) to medium-high heat, around 200°C (400°F). Thread the marinated chicken pieces onto skewers if using, or place them directly on the grill grates. Grill the chicken for about 6-8 minutes per side, or until cooked through and nicely charred. The internal temperature should reach 74°C (165°F).

Warm the Pita Bread: While the chicken is grilling or resting, warm the pita bread. You can do this by lightly toasting them on the grill for about 30 seconds per side, warming them in a dry skillet over medium heat for about 1 minute per side, or wrapping them in foil and warming them in a low oven (150°C / 300°F) for about 5-10 minutes.

Assemble the Gyros: Lay a warm pita flat. Spread a generous layer of tzatziki sauce over one half of the pita. Top with a portion of the grilled chicken, followed by sliced tomatoes, red onion, and a sprinkle of fresh parsley.

Serve: Fold the other half of the pita over the filling to create a wrap. Serve immediately and enjoy your homemade Greek chicken gyros!