In a mini food processor, add in all the garlic sauce ingredients and blend. Pour in a bowl and set aside in the fridge.
In a large bowl, add the ground beef, grated onion, garlic, parsley, mint, lemon zest, sumac, cumin, cinnamon, salt, and pepper. Mix well with your hands.
Form even patties and add salt and pepper on both sides of the patties.
In a cast-iron skillet or grill, add the avocado oil, grill the burgers for about 3-4 minutes per side.
On your butter lettuce, add the burger, the garlic spread, pickled red onions, more mint, parsley, crumbled feta, and enjoy!