Slow-Cooker Chicken and Pasta Soup

4 carrots, quartered lengthwise and cut into 1-inch pieces
4 long strips lemon zest
4 sprigs fresh dill, plus 2 to 3 tablespoons chopped
2 tablespoons extra-virgin olive oil
Kosher salt
4 skinless, boneless chicken breasts (1 ½ to 2 pounds)
4 cups chicken broth
1 cup small pasta, such as pastina (we used tiny stars)
1 cup frozen peas, thawed
½ bunch fresh spinach, stemmed
Freshly ground pepper
4 ounces feta cheese
Lemon wedges and crusty bread, for serving

Combine the carrots, lemon zest, dill sprigs, olive oil and ½ teaspoon salt in a 5 to 6-quart slow-cooker. Season the chicken with salt and add to the cooker. Add the broth and 4 cups water, cover and cook on low, about 8 hours.

About 20 minutes before serving, add the pasta to the slow cooker, cover and cook until tender, about 15 minutes.

Stir the chopped dill, peas and spinach into the soup and cover until the spinach wilts, about 2 minutes. Stir to break up the chicken and season with salt and pepper. Ladle into bowls and crumble the feta on top. Serve with lemon and bread, if desired.