Here is the recipe
1 med onion, cut into chunks
1 pound ground lamb
1 pound ground beef
1 tablespoon minced garlic
1 heaping teaspoon dried oregano
1 heaping teaspoon ground cumin
1 heaping teaspoon dried marjoram
1 heaping teaspoon ground dried rosemary
1 heaping teaspoon ground dried thyme
1 heaping teaspoon ground black pepper
2 teaspoon kosher salt or more to taste
Place the onion in a food processor, and process until finely chopped. Add ground beef and lamb then the garlic, oregano, cumin, marjoram, rosemary, thyme, black pepper, and salt. Process into a paste. Cover, and refrigerate 1 to 2 hours to allow the flavors to blend.
Grill indirect 350 for 45 minutes the take out of foil pan and cook another 30 minutes. Rest 1 hr.
1 pound (1 pint) plain nonfat greek yogurt
1 hothouse cucumber, unpeeled and seeded
2 tsp plus 1/2 teaspoon kosher salt
1/2 cup sour cream
1 tablespoon Champagne vinegar or white wine vinegar
2 tablespoons freshly squeezed lemon juice (1 lemon)
1 tablespoon good olive oil
1 1/2 teaspoons grated garlic
1 1/2 teaspoons minced fresh dill
Pinch freshly ground black pepper
Grate the cucumber and toss it with 2 tsp of kosher salt; place it in another sieve, and set it over another bowl for 30 minutes.
Transfer yogurt to a large bowl. Squeeze as much liquid from the cucumber as you can and add the cucumber to the yogurt. Mix in the sour cream, vinegar, lemon juice, olive oil, garlic, dill, 1/2 teaspoon salt, and pepper. You can serve it immediately, but I prefer to allow the tzatziki to sit in the refrigerator for a few hours for the flavors to blend. Serve chilled or at room temperature.