1 small white onion, peeled and cut into 1/4-inch rounds
2 tablespoons olive oil
1 cup fresh cilantro leaves, plus more for garnish
Kosher salt and freshly ground black pepper
1 cup Mexican-style crema
1 lime, zested and juiced
Heat a grill or grill pan over medium-high heat.
Toss the jalapenos and onion rounds in the olive oil in a bowl. Grill the jalapenos and onion rounds until charred all over, turning as needed, about 5 minutes total. Place the jalapenos in a bowl and cover tightly with plastic wrap for 10 minutes. Set the onions aside.
Cut the jalapenos in half, remove the stems and seeds and gently scrape off the charred skin. Roughly chop the grilled onion rounds.
Combine the jalapenos, onion, cilantro and some salt and pepper in a food processor. Pulse in 2-second increments until finely minced.
Whisk together the crema and lime zest and juice in a medium bowl. Add the jalapeno-onion mixture to the bowl with the crema and fold everything together until fully incorporated.
Pour into a serving dish and garnish with cilantro leaves. Serve as a flavorful topping on your favorite tacos.