Think of this as a relish-type side: You don’t need a big serving, but the bright flavor is a welcome addition to roasted meat and hearty casseroles. Red pearl onions are gorgeous, but you can use white pearl onions, too. And if you’re really crunched for time, go with frozen pearl onions: Thaw them first and drain off any liquid (and you can skip step 1).
How to Make It
Bring a large pot of water to a boil, and add onions. Boil 30 seconds; drain and immediately plunge into a bowl of ice water. Trim root end of each onion, leaving core intact; squeeze gently from top of each onion to remove tough outer skin. Discard skins, and place peeled blanched onions in a bowl.
Heat butter in a large nonstick skillet over medium-high. Once butter is sizzling, add onions in a single layer. Cover and cook, stirring often, until onions are lightly caramelized, 8 to 10 minutes.
While onions cook, whisk together brown sugar, cumin, kosher salt, 1 teaspoon lime zest, and lime juice in a small bowl; pour into skillet, and toss to coat onions. Cover and cook over medium, stirring occasionally, until mixture is syrupy and onions are tender, 5 to 6 minutes.
Spoon onions and sauce onto a platter; sprinkle with flaky sea salt and remaining 1/2 teaspoon lime zest. Serve immediately.