Preheat Oven to 450° and place oven rack in the center
Mix together (Flax Egg) 1 Tbsp. flax seed meal and the 3 Tbsp. warm waterSet aside while you work on the rest of the recipe In a food processor place the following ingredients: 1/2 Onion1 Handful spinach2 Cloves garlicPulse until all ingredients are chopped and mixed together In a large bowl, add Impossible Burger, dried spices, fresh parsley, tomato paste, salt, panko, flax egg, onion, spinach and garlic mixture,add salt and pepper to taste. Mix all ingredients together until fully incorporated.
Gently roll balls into 1" diameter(About the size of a golf ball. This mixture will make about 12). Place on a rimmed baking sheet, spacing evenly apart. Bake meatballs until browned and cooked through, 10 minutes. Flip them over and cook for another 5 making sure they don't get too brown.
Meanwhile, make the Creamy Garlic Tzatziki Sauce. (This can be made the night before and stored in the refrigerator in a glass container with a tight lid).
Slice cucumbers in half lengthwise. Scoop out any seeds even if they are small.
Using food processor grate attachment, grate all 3 cucumbers. If you don't have a grate attachment a box grater will work.
Place the shredded cucumber in the middle of a kitchen towel or paper towel and squeeze to remove extra liquid. Place shredded cucumber, sour cream, lemon juice, garlic and milk in a bowl and mix to incorporate.
Transfur all ingredients into the food processor using an S-blade attachment. Pulse for 30 seconds until mixture is smooth. If the mixture looks to thick, add more milk one tablespoon at a time.