Preheat your sous vide water bath to 60 degrees C.

Place the beef, pork, mint, salt, cayenne, and oregano in a medium mixing bowl.

In a small sauté pan, cook the shallots and garlic over medium low heat in 1 tablespoon of the oil until tender and translucent. When cool, add the shallot mixture to the meat along with the breadcrumbs, yogurt, egg, and lemon zest; mix gently but thoroughly to combine. Form the meat mixture into slightly flattened meatballs (about 2 tablespoons each) and transfer the patties to two resealable freezer food storage bags.  Seal each bag using the water displacement method, lower both bags into the water bath and cook (completely submerged), for 1 hour. Remove the bags from the water and discard the liquid in the bags. Transfer the patties to a plate or platter.

Heat a large nonstick skillet over medium heat and add the remaining olive oil. Cook the meat patties (in batches if necessary) until browned on both sides, 2 to 3 minutes. Transfer the patties to a serving platter and garnish with mint leaves. Serve with pita bread, lettuce, tomatoes, and yogurt if desired.