Lemon-Basil Beef Meatballs, Balsamic Mushroom Sauce

Steps

1. Preheat the oven to 425°F (220°C) and line two sheet pans with parchment.
2. Prep first: cube the sweet potato, cut the asparagus, wedge the red onion, slice the mushrooms, chop the parsley and basil, and mince the garlic, setting half the garlic aside for the meatballs and half for the sauce.
3. On one sheet pan, toss the sweet potato and red onion with two-thirds of the olive oil, the rosemary, a quarter of the salt and a quarter of the black pepper. Roast for 10 minutes.
4. Meanwhile, in a large bowl, mix the egg, breadcrumbs, parmesan, parsley, basil, the first half of the garlic, the lemon zest, the oregano, half the salt and half the black pepper. Add the beef and mix gently just until combined.
5. Roll the beef mixture into 20 balls and set them on the second sheet pan.
6. Stir the sweet potato and onion, add the asparagus to that pan and toss it in the oil on the pan. Return it to the oven with the meatball pan and roast both for 15 to 18 minutes, until the vegetables are browned and the meatballs reach 160°F (71°C) in the center.
7. While they roast, heat the remaining one-third of the olive oil in a large skillet over medium-high heat. Add the mushrooms and cook without stirring for 3 minutes, then stir and cook 4 minutes more until browned.
8. Add the remaining half of the garlic and the thyme to the mushrooms and cook 30 seconds. Pour in the beef broth and balsamic and simmer 3 minutes.
9. Stir the cornstarch into the cold water, then stir this slurry into the skillet and simmer 1 to 2 minutes until glossy and thickened. Season with the remaining quarter of the salt and the remaining quarter of the black pepper.
10. Take the skillet off the heat, let it cool for 1 minute, then stir in the Greek yogurt until creamy. Add the meatballs and turn them in the sauce.
11. Serve the meatballs and mushroom sauce with the roasted sweet potato, asparagus and red onion.