Combine the prunes and Sherry in a small bowl and let stand 1 hour.
Preheat the oven to 350 F.
Place the chicken in a re-sealable plastic bag and put the bag in a shallow baking dish. Puree the garlic, cilantro and orange juice in a blender, pour over the chicken in the bag and seal the bag, pressing out excess air. Marinate, chilled, 1 hour.
Place almonds in shallow baking dish or pie plate and bake for 5 to 6 minutes or until golden.
Pat the chicken dry and sprinkle all over with salt and pepper. (Discard the marinade.) Dredge the chicken lightly in flour, shaking off excess. Heat the oil in a 12-inch heavy skillet over moderately high heat until hot but not smoking, then brown the chicken in two batches, if necessary, starting with skin sides down and turning over once, 8 to 10 minutes per batch. Transfer the chicken as browned to a plate and discard the oil from skillet. Drain the prunes in a sieve set over a small bowl, reserving the prunes and the Sherry.
Remove the pan from the burner. Add the Sherry to skillet (use caution; it may ignite) and cook over moderately high heat, stirring and scraping up brown bits, 1 minute. Then add the broth. Return the chicken, skin sides up, to the skillet along with any juices accumulated on plate, the olives and the prunes.
Transfer the skillet to the middle shelf of the oven and bake it until just cooked through, about 20 minutes. Transfer the chicken with tongs to a serving dish and, if sauce is too thin, boil, uncovered, stirring occasionally, until thickened, 1 to 2 minutes. Remove from the heat, add the butter and stir until incorporated; add salt and pepper to taste. Pour sauce over chicken. Garnish with almonds and additional cilantro.
Recipe courtesy of Sara Moulton from the public television series ‘Sara’s Weeknight Meals’ sponsored by Sunsweet. For more information, go to saramoulton.com/weeknightmeals.