And once you have the meatball 'formula' down, you can tweak it any way you like. My formula is an egg and half a cup of some kind of bread crumb for every pound of ground meat. The rest is up for grabs.
For these meatballs I added a little extra in the way of spices---cardamom, cumin, allspice and lots of salt and pepper. Cinnamon can be substitued for the cardamom if you don't have any. I love the exotic combinations of spices in Middle Eastern meats. You can experiment with other spices, too, like paprika, coriander, turmeric, ginger, nutmeg and chilies.
I also used a heavy hand with the greens...scallion, parsley and mint.
2 cups yogurt
1/4 cup tahini (optional)
1/2 cup cilantro, parsley, mint, or a combination, finely minced
juice of 1 lemon
1 clove garlic, minced
salt to taste
For the meatballs: Put everything except the olive oil into a large bowl. Make sure you egg is pre-beaten. With as little manipulation as possible, combine all the ingredients thoroughly together. The less you work the mixture the more tender your meatballs will be. Form into small balls and set on a plate. Using a scooper makes the process clean and easy. Mine was 1 3/4 inch. If you want to do this part ahead, you can, just cover with plastic wrap and refrigerate till you're ready to cook. Heat a couple of tablespoons of olive oil in a skillet and brown the meatballs, in batches, for several minutes, turning them once or twice in the pan. Transfer the meatballs to a baking sheet and bake for about 10 to 15 minutes, until done. The time will depend on the size of your meatballs, I like to use my cooking thermometer to check one; it should read about 160 degrees. They will continue to cook a bit after they're out. For the sauce mix up all the ingredients and thin with a little milk if it seems too thick. This can be made ahead. Serve the meatballs with the sauce and a few pine nuts for garnish.