Slice the Chicken: Slice the top of each chicken breast, making 5-7 angled slits about halfway down, without cutting through. This helps the chicken cook faster and more evenly, and creates more surface area for the marinade and sauce to coat the chicken.
Marinate the Chicken: In a small bowl, combine garlic powder, smoked paprika, black pepper, and rosemary. Rub this mixture over the chicken breasts and set aside.
Sear the Chicken: Heat olive oil in a large skillet over medium-high heat. Sear the chicken for 4 minutes on each side, or until golden and cooked through. Remove the chicken and set aside.
Cook the Base: In the same pan, fry the onion over medium heat until caramelised, about 5 minutes. Add garlic and cook for another minute. Add smoked paprika, oregano, red chilli flakes, Italian seasoning, salt, and black pepper, and stir well.
Add Vegetables: Add the mushrooms, bell peppers, and cashews to the pan. Cook for about 2-3 minutes, stirring occasionally.
Prepare the Sauce: Reduce the heat to low-medium. In a small bowl, whisk together chickpea flour and water until smooth. Add it to the pan, along with chicken stock and heavy cream. Bring the mixture to a simmer.
Finish Cooking: Add the spinach, cherry tomatoes, red fresh chilli (if using), and the seared chicken back to the pan. Simmer for about 10 minutes, or until the sauce thickens and the chicken is heated through.
Serve: Serve hot with your choice of side dish or enjoy on its own.