Roast the Goldenberries, jalapeño, onion and garlic on a rimmed baking sheet 4 inches below a broiler, until blotchy black and softening, about 5 minutes. Flip them over and roast the other side. Cool, and then transfer everything to a blender. Add the cilantro and 2 tablespoons of water (or chicken stock), and then blend to a coarse puree. Set aside.