Meyer Lemon Pasta with Chicken and Baby Spinach

Name: Meyer Lemon Pasta with Chicken and Baby Spinach
Ingredients: 1 pound spaghetti, linguini or other pasta; 3 tablespoons extra-virgin olive oil; 1 red bell pepper seeded, deveined and cut into strips (optional); 1 white, yellow, or sweet onion, peeled and sliced into strips; 2 cloves garlic, minced; 5 ounces baby spinach leaves, rinsed and spun dry; grated zest of 1 Meyer lemon, (Eureka lemon is also fine); 1 breast of turkey or 2 breasts of chicken or 2 thighs, skinned, pulled off the bone and torn into bite-size pieces; juice of 1/2 to one lemon, strained to remove seeds; salt and pepper to taste; Pinch red pepper flakes (optional)