Make the meatballs
Preheat the oven to 425ºF. Set a rack on a baking sheet.
Toast the pine nuts in a small skillet over medium heat for 3 to 4 minutes, stirring so that they don’t burn. Transfer to a plate to cool, then chop them.
Put the lamb in a large bowl. Flatten it out, sprinkle the pine nuts, ras el hanout, salt, and garlic over it, and mix well by hand. To test for seasonings, flatten a tablespoon of the mixture into a patty, sear it in a small nonstick skillet over medium-high heat, and taste it. Add more salt and/or ras el hanout if necessary to the rest of the lamb mixture.
Moisten your hands and form the lamb mixture into 8 meatballs, about 2 inches in diameter, moistening your hands again if the mixture starts to stick. Arrange on the rack on the baking sheet and bake for 15 minutes, or until golden brown. Remove the meatballs from the oven and let stand for 5 minutes to finish cooking.
Make the sauce
Put the yogurt in a bowl and season with salt and white pepper to taste. Stir in the oil. Slowly add up to 1/2 cup water, until the sauce is the consistency you like. Stir in the parsley.
Put the meatballs on a platter, spoon the sauce over them, and serve.