Like baseball mitts, cast iron skillets, and George Clooney, some things improve with time. Others, not so much—off the top of my head, I'm thinking knees, Teflon pans, and Mickey Rourke. Likewise, many sauces improve with extra time in the pot, but meatballs don't. Once cooked, they just get drier and tougher the longer they simmer. This presents a dilemma when you're making something like slow-cooker meatballs in a rich, flavorful sauce.
Kenji grappled with this problem when making his slow-cooker Italian-American meatballs in tomato sauce. His solution: Cook the sauce in a slow cooker until its flavors have fully deepened and melded, then add the meatballs just long enough to cook them through while keeping them tender and juicy. So that's exactly what I did with this recipe for slow-cooker chicken meatballs in a sticky Thai sauce.
To start, I combine lemongrass, jalapeño, ginger, garlic, shallots, and fish sauce in my food processor and blend them into a smooth paste. (You could use a mortar and pestle for even better flavor and texture, but that'd go against the convenience that a slow-cooker recipe promises.) These are the biggest flavors in the dish, and I use them to flavor both the meatballs and the sauce.
For the sauce, I sauté half of the paste before adding Thai chili sauce, sugar, rice vinegar, and soy sauce and cooking them together briefly. It's important to make sure you have Thai chili sauce—many other Asian chili sauces are exponentially hotter and would result in unbearably spicy meatballs. Then I pour in water to give the mixture enough moisture to cook without burning as it reduces to a sticky consistency.
Once the sauce is reduced, I transfer it to my slow cooker to continue cooking and developing flavor. I like to set my sauce to cook overnight for about eight hours on low, but if you're shorter on time, five to six hours will do. Either way, all those hours in a slow cooker will deliver a sauce with a smoother, less aggressive flavor than if you cooked the same sauce just long enough to reduce it to the proper consistency. (I know this because I tried it.)
For the meatballs, I mix the remaining aromatic paste with ground chicken, scallion, egg, and panko bread crumbs. Then I brown the meatballs in a broiler to deepen their flavor and add them to that slow-cooked sauce. After 30 minutes, they're cooked through, but still tender and juicy.
Right before serving, I toss together additional scallion, cilantro, crushed peanuts, and lime juice to top the meatballs. After I sprinkle the mixture over and stir a bit, the meatballs are ready for eating. You can even make these ahead of a party or potluck and hold them using the slow cooker's warm setting. It's a low enough temperature that there's no need to worry about the effects of time on the final dish's quality...which makes this recipe...timeless?