Heat one teaspoon of olive oil in a non-stick pan over medium heat.
Season the chicken cubes with salt and pepper. Add the chicken to the pan and cook for 5-7 minutes, or until golden brown and fully cooked. Remove the chicken from the pan and set it aside.
In the same pan, add another teaspoon of olive oil. Add the chopped onion and sauté for 3-4 minutes over medium heat until it softens and becomes translucent.
Add the minced garlic and grated ginger, and stir for an additional minute until fragrant.
Add the turmeric, cumin, and black pepper. Stir the spices for 30 seconds to toast them and release their flavor.
Pour in the chicken broth and bring the mixture to a boil. Then reduce the heat and let it simmer for 5 minutes until the sauce thickens slightly.
Remove the pan from the heat, then add the Greek yogurt and lemon juice. Stir the ingredients well until the sauce is smooth. Season with salt to taste.
Return the cooked chicken to the sauce, and stir well until the chicken is coated.
Warm the dish over low heat for just one or two minutes to let the chicken and sauce meld together.
Serve the turmeric sauce chicken hot.