Heat a drizzle of oil in a pan over medium heat.

Add the onions and cook until they are translucent.

Add the chicken pieces and cook until they are lightly browned on all sides.

Stir in the mushrooms and cook until they start to release their juices.

Mix in the tomato paste, allowing it to coat the chicken and mushrooms.

Pour in the chicken stock, lemon juice, and sprinkle with paprika, garlic powder, and thyme. Stir well to combine.

Bring the mixture to a simmer and let it cook until the chicken is cooked through and the sauce has thickened slightly.

Remove the pan from the heat and stir in the sour cream until the sauce is smooth and creamy.

Season generously with salt and pepper to taste.