Nutrition per serving may change if servings are adjusted.
8 ounces ground beef, 90%-lean or leaner
8 ounces ground lamb
1/3 cup lemon juice
1 small onion, quartered
2 cloves garlic, peeled
8 pitted green olives
2 tablespoons extra-virgin olive oil
1/4 cup chopped fresh cilantro
2 tablespoons chopped fresh parsley
1 tablespoon ground cumin, plus more for serving
1/2 teaspoon salt
1/2 teaspoon freshly ground pepper
Harissa, (see Ingredient Note) for serving
Place beef, lamb and lemon juice in a large bowl. Gently combine until incorporated. Marinate in the refrigerator for 1 hour.
Transfer the meat to a colander and press to squeeze out excess moisture. Place onion, garlic and olives in a food processor and pulse until coarsely chopped. Add to the marinated meat along with oil, cilantro, parsley, 1 tablespoon cumin, salt and pepper. Gently combine until evenly incorporated.
Position rack in upper third of oven; preheat broiler. Line a large rimmed baking sheet with foil and set a wire rack on it.
Using about 3 tablespoons of the meat mixture for each, form 12 thin patties, about 2 1/2 inches wide and 1/4 inch thick. Place on the wire rack.
Broil the patties until brown and cooked through, 8 to 10 minutes. Serve with additional cumin and harissa, if desired.
Ingredient note: Harissa is a fiery Tunisian chile paste commonly used in North African cooking. Find it at specialty-food stores, mustaphas.com or amazon.com. Harissa in a tube will be much hotter than that in a jar. You can substitute Chinese or Thai chile-garlic sauce for it.