A great cobbler is all about the contrast between bubbling, juicy fruit and a golden, baked biscuit topping. In this recipe, ripe nectarines and plump blackberries create a sweet-tart filling that bubbles beneath a layer of tender, buttery drop biscuits with toasty edges. Rather than rolling or cutting the dough, spoonfuls of soft biscuit dough are dropped directly over the fruit, forming crisp, golden mounds with fluffy centers.