First, make the meatballs: Combine the ground beef, panko, yogurt, lemon zest and 1 ½ teaspoon each Berbere spice and salt in a large mixing bowl. Mix until everything is well combined.
Form the meat mixture into roughly 2-inch balls, using your hands or a 1-ounce ice cream scoop. Refrigerate until ready to use (this will help them keep their shape).
Heat the olive oil in a large dutch oven or saucepan over medium heat. Add in the onion and saute until tender, about 5 minutes.
Add in garlic and a large pinch (about ½ teaspoon each) of salt and Berbere spice. Continue sauteing until fragrant and the onions begin to turn golden brown and translucent, about 5 minutes more.
Using your hands, crush the whole peeled tomatoes into the pot. Add in the diced tomatoes and season with 1 more teaspoon of Berbere spice and salt. (note: our Berbere spice blend has a kick. If you don’t prefer spice, cut back a bit).
Bring the mixture to a boil, then reduce the heat to a simmer. Let simmer for about 15 minutes, allowing the sauce to thicken and flavor to meld.
Carefully add the meatballs to the pot in a single layer. Cover, and continue simmering, untouched, for about 25 minutes more (do not stir the meatballs during this time, they need to cook untouched to keep their shape).
Remove the lid and stir in the feta and fresh herbs. Let simmer for about 5 minutes more, then serve warm alongside crusty bread for dipping in the delicious sace.
