At the London takeaway restaurant Leon, Moroccan meatballs made from lamb were once simmered in a harissa-spiked tomato sauce, served over peppery arugula, and drizzled with bright yogurt-thickened aïoli.

Ingreadients:

• ½ cup whole milk
•  One 10-in. whole wheat pita, torn into 1-in. pieces
• 2 lb. ground lamb
• 1½ cups finely chopped parsley, divided
• ¾ cup finely chopped mint
• 1 tsp. dried oregano
• 9 cloves garlic; 6 finely chopped, 3 peeled and crushed, divided
•  Kosher salt and freshly ground black pepper, to taste
• 2 Tbsp. olive oil, divided
•  One 28-oz. can whole peeled tomatoes, crushed by hand
• 1½ Tbsp. harissa
• 2 large egg yolks
• ½ cup canola oil
• ¾ cup Greek yogurt
• 1 Tbsp. fresh lemon juice
• 8 cups baby arugula
• 16 cherry tomatoes, halved
• ½ cup coarsely chopped basil

Direction

1. In a large bowl, toss together the milk and pita in a bowl. Set aside until the bread is softened, about 5 minutes. Add lamb, 1 cup of the parsley, the mint, oregano, and a quarter of the chopped garlic. Season with salt, and black pepper, then mix well to combine. Divide the mixture into thirty-six 1-ounce balls.
2. To a medium pot over medium-high heat, add 1 tablespoon olive oil. When the oil begins to shimmer, working in batches, cook the meatballs, turning occasionally, until browned all over, 4–6 minutes. Transfer to a plate and set aside.
3. Add the remaining olive oil to the pot and return to medium-high heat. When the oil begins to shimmer, add the crushed garlic and cook, stirring frequently, until golden and fragrant, 1–2 minutes. Stir in the canned tomatoes and harissa, season lightly with salt and black pepper, bring to a simmer, then turn the heat down to medium and cook until the sauce is slightly thickened, 5–7 minutes. Return the reserved meatballs to the pot, cover, and cook, until the meatballs are tender and cooked through, about 15 minutes, then remove from the heat.
4. Meanwhile, make the aïoli: In a medium bowl, whisk together the remaining chopped garlic, the egg yolks, and a pinch of salt and black pepper. While whisking, very slowly drizzle in the canola oil until the aïoli is emulsified, thick, and creamy. Whisk in the yogurt and lemon juice, then season to taste with more salt and black pepper as needed.  
5. Arrange the arugula and cherry tomatoes over a platter and top with the meatballs and some of their sauce. Drizzle the aïoli over the meatballs, and garnish with the remaining parsley and the basil. Serve hot, with additional tomato sauce on the side.