Heat the oil in a deep frying pan to a high heat and add the chicken, cauliflower, garlic, and salt. Cook for about 8 minutes, tossing frequently, until the chicken is cooked through. Remove from the heat and add the baby spinach, ¼ cup Parmesan, sour cream, and lemon juice. Stir gently and season to taste with black pepper and extra salt if required.
At the same time the chicken is cooking, heat a second frying pan on medium and add the gnocchi. Cook for about 4 minutes without stirring until browned on one side, then mix in the butter and chopped pistachios and cook for another 3 minutes until the pistachios are lightly browned.
Tip the gnocchi and pistachios into the pan with the chicken. Add 2 tablespoons of water to loosen it and mix gently. Serve with extra grated Parmesan and rocket on top.