In a food processor add spinach, almonds, basil, garlic cloves, parmesan cheese and blend until the ingredients are finely chopped. Add water to make a smooth paste.
Add lemon juice and season with salt.
Add oil in a cast iron skillet and saute onion until light brown. Add red pepper and mushrooms and cook until soft.
Toss in chicken and cook until the color is changed.
Stir in pesto to coat and let it simmer. Season with salt and serve hot.
Keyword 20-minute Skillet Pesto Chicken, One Pan meal, Pesto Chicken