Make the marinade: In a large mixing bowl, whisk together the yogurt, olive oil, lemon juice, minced garlic, dried oregano, salt, and pepper. The mixture should look pale yellow and smell bright and herbaceous — that sharp lemon-garlic aroma tells you it's balanced.

Marinate the chicken: Add the chicken thighs to the bowl and turn them with your hands until each piece is fully coated. You'll feel the yogurt mixture clinging to the meat — it should be glossy, not dripping. Cover with cling film and refrigerate for at least 30 minutes, or up to 24 hours for deeper flavour.

Preheat your grill or grill pan: Set it to medium-high heat (about 200°C). Let it heat for a full 5 minutes — you'll see a faint shimmer of heat rising from the surface when it's ready. A drop of water should sizzle and evaporate immediately.

Grill the chicken: Place the thighs on the hot grill, leaving space between each piece. You should hear a satisfying sizzle as the meat hits the surface — if it's silent, the grill isn't hot enough. Cook for 5–6 minutes without moving them.

Flip and finish: Use tongs to flip each piece. The cooked side should be golden-brown with distinct grill marks and a slightly crispy edge. Cook for another 4–5 minutes, until the internal temperature reaches 74°C and the juices run clear when you pierce the thickest part with a knife.

Rest the chicken: Transfer the thighs to a cutting board and let them rest for 5 minutes. You'll see the juices settling back into the meat rather than pooling on the board — this keeps every bite moist.

Slice and serve: Slice each thigh against the grain into thick strips. The inside should be white and juicy, not pink, with a faint herb-flecked crust on the outside. Scatter over the red onion slices, fresh parsley, and a squeeze of lemon.