Dice the chicken breast into bite-sized pieces and season lightly with a pinch of the salt and pepper.
Heat the olive oil in a large skillet over medium-high heat.
Add the chicken to the skillet and sear until golden brown on all sides, then remove chicken and set aside.
In the same skillet, add the diced onion and minced garlic, sautéing for 2-3 minutes until softened and fragrant.
Stir in the curry powder, turmeric, remaining sea salt, and black pepper, toasting the spices for 30 seconds.
Pour in the tomato puree and full-fat coconut milk, whisking gently to combine into a smooth sauce.
Return the chicken to the skillet and reduce heat to low, simmering for 5-7 minutes until the sauce thickens and chicken is cooked through.
Fold in the fresh baby spinach and stir until just wilted.
Garnish with freshly chopped cilantro and serve warm.