Preparation:
Place a rack in center of oven; preheat to 425 degrees. Finely grate 1 garlic clove into a medium bowl. Finely grate 1 more garlic clove into a small bowl. The medium bowl is for your meatball mixture and the small bowl is for your salsa verde, in case this part seems silly. Finely chop 2 cups mixed herbs. As we mentioned in the ingredients list, you can use any combo of soft herbs like parsley, dill, basil and/or cilantro, but if you've only got one that's cool, too—we just love how green and complex they taste when mixed together. Transfer half to same medium bowl, then transfer remaining herbs to same small bowl. Finely chop 3 tablespoons capers. Transfer 2 tablespoons capers to medium bowl, then transfer remaining 1 tablespoon capers to small bowl. Chop ¼ cup walnuts and add to same medium bowl. If you've never added nuts to meatballs, you're in for a real treat; they lend great texture and flavor to the finished dish. Whisk in 1 egg, 1 tablespoon paprika, 2 teaspoons salt, and 1 tablespoon oil to bowl with walnuts. Using clean hands, mix 1 cup panko into egg mixture. Add 1 pound ground beef and continue to mix gently with your hands until incorporated, but do not over-mix. This part is key—if you work the mixture too much, the meat will become tough and springy, almost like sausage, so use a gentle hand. Also: At this point, you can pinch off a little piece of the meatball mixture, crisp it in a skillet, and give it a taste to make sure the seasoning is to your liking. This is your last chance to make any tweaks before they all get cooked! Drizzle 2 tablespoons oil on a rimmed baking sheet. Roll beef mixture into 1½ inch balls (about the size of golf balls). Arrange 1 inch apart on pan. Bake meatballs, shaking pan halfway through, until crispy on all sides, about 10 minutes. One cool thing about using all beef (instead of a beef-pork-veal combo) is that it's totally fine if the meatballs are a little pink in the middle.
While meatballs are cooking, you can finish that salsa verde. This is one of our all-time favorite sauces, and is delicious spooned over just about any piece of meat, roasted veggie or bowl of leftovers you can think of. Which is all to say: Get ready to have a lot more salsa verde in your life from here on out. Finely grate lemon zest into bowl with herbs and garlic. Halve the lemon you just zested and squeeze juice into bowl, using your hand to catch any seeds. You can use a citrus squeezer for this if you've got one. Add remaining ½ cup oil and stir to combine. Season with salt and pepper, taste and add more seasoning if necessary—it should be good and punchy. Transfer meatballs to a platter and serve with salsa verde alongside.
