Preheat oven to 425 degrees. Coat a baking dish with cooking spray.
- Cut 1 lb. boneless skinless chicken breast into 1-inch pieces. Sprinkle with black pepper.
- Heat 1 tablespoon olive oil in nonstick skillet over medium heat. Add chicken pieces and cook for 2 minutes until golden brown. Turn chicken pieces and cook the other side for 2 minutes.
- Add 2 medium yellow onions, thinly sliced. Cook until tender. Add 2 teaspoons minced garlic and cook for 1 minute.
- Stir in 2 (19-ounce) cans rinsed cannellini beans and ¾ cup water. Simmer for 3 minutes, stirring ingredients. Transfer to baking dish. Cover and bake in hot oven for 10 minutes.
- Bring water to a boil in pot. Add 1 (10-ounce) package fresh baby spinach. Cook for only 30 seconds. Remove from water with a slotted spoon.
- Add cooked, drained spinach to the bean casserole; stir gently to combine.
- Return to oven, covered, and bake for 15 minutes.
Makes 6 servings.