Slice the chicken breast to even out thickness and cut into two pieces.

Place chicken, yogurt, garlic, salt, and pepper in a bag and massage to coat. Let marinate for 10 minutes.

Dice the tomato into 1cm cubes and chop the onion roughly.

Microwave the chopped onion in a heatproof container for 1 minute at 600W, then let cool. Mix with remaining tomato sauce ingredients.

Heat 2 tsp olive oil in a pan over medium heat. Place chicken skin-side down and cook until browned. Flip, cover, and steam for 5 minutes until cooked through.