Lamb Burgers with Tzatziki Sauce

Ingredients

• 1/4 cup bread crumbs
• 1/4 cup onion, minced
• 1/4 cup feta cheese
• 1 large egg, beaten
• 1 clove garlic, minced
• 1/4 cup fresh mint, minced
• 1 teaspoon kosher salt
• 1 teaspoon ground cumin
• 1 teaspoon ground coriander
• 1/4 teaspoon ground cinnamon
• 1/4 teaspoon red pepper flakes
• 1 pound ground lamb
• 1/2 English cucumber, grated
• 1 cup plain Greek yogurt
• 2 tablespoons fresh mint, minced
• Juice of 1 lemon
• 1 tablespoon extra virgin olive oil
• 1/4 teaspoon ground black pepper
• Optional: 4 hamburger buns