Chicken in Oaxaca Yellow Mole with Green Beans and Chayote (or Potatoes)

Ingredients

4 (1 ounce total) dried guajillo chiles, stemmed and torn into several pieces each
Half a 15-ounce can diced tomatoes in juice (preferable fire-roasted), drained
½ small white onion, cut into 4 pieces
2 garlic cloves, peeled and halved
¼ teaspoon each ground cumin, allspice and cinnamon, preferable Mexican canela
1 teaspoon dried oregano, preferably Mexican
4 cups chicken broth
2 tablespoons vegetable or olive oil
1 tablespoon powdered masa harina (Mexican corn “flour” for making tortillas – look for it in well-stocked groceries)
4 (1 pound total) boneless, skinless chicken thighs, cut into 1-inch cubes
6 ounces green beans, tops and tails broken off and cut into 2-inch pieces (you need about 2 cups)
2 large (1 pound total) chayotes, peeled (if you wish), pitted and cut into 1-inch cubes OR 4 medium (1 pound total) red-skin boiling or Yukon Gold potatoes, peeled (if you wish) and cut into 1-inch cubes
Salt
1 to 2 fresh hoja santa leaves, torn into 1-inch pieces OR ½ cup (or more) roughly chopped cilantro

In a blender jar, combine the torn guajillo chiles, tomatoes, onion, garlic, spices, oregano and 1 cup of the chicken broth. Blend until as smooth as possible. (A food processor will work, but it won’t completely puree the chile.)
In a medium-large (4- to 6- quart) heavy pot, heat the oil over medium-high. Set a medium-mesh strainer over the top and pour in the chile mixture; press the mixture through the strainer into the hot oil. Cook, stirring, until the mixture is reduced to the consistency of tomato paste, about 5 minutes.
Whisk the masa harina into the remaining 3 cups broth, then pour into the cooked chile mixture. Whisk until the sauce comes to a boil and thickens to the consistency of a light cream soup. Reduce the heat to medium-low. Add the chicken, green beans, chayote or potatoes and 1 teaspoon salt. Simmer gently, stirring regularly, for about 20 minutes, until all the chicken and vegetables are tender.
Add the hoja santa or cilantro, then taste and season with salt, usually between ½ and 1 teaspoon, depending on the saltiness of your chicken broth, and serve.