Step 1

In a 12-inch skillet over medium-high, heat the oil until barely smoking. Add the chilies and cook, stirring occasionally, until charred in spots, 2 to 4 minutes. Reduce to medium and add the garlic, onion, ¼ cup water and ½ teaspoon salt. Cover and cook, stirring often, until the vegetables are softened, 5 to 7 minutes. Meanwhile, in a small bowl, toss the shrimp with the lime juice, ½ teaspoon salt and ¼ teaspoon pepper; set aside.

Step 2

Transfer the vegetable mixture to a blender; reserve the skillet. To the blender, add the cilantro, crema and ¼ teaspoon each salt and pepper. Blend on high until smooth, 1 to 2 minutes.

Step 3

Pour the puree into the skillet and bring to a simmer over medium. Cook, stirring occasionally, until slightly thickened, 3 to 5 minutes. Add the shrimp and cook, stirring often, until opaque throughout, about 3 minutes.

Step 4

Off heat, taste and season with salt and pepper. Transfer to a serving dish and garnish with additional cilantro and sliced onion; serve with lime wedges.