The size and color of a ping-pong ball, the rare frutilla blanca grows only in about two-dozen gardens in the steep forested slopes of the Nahuelbuta Range. It has a sugary flavor and pineapple-like fragrance that makes it entirely distinct from a standard strawberry. It also happens to be an ancestor of garden-variety strawberries. Chile’s Indigenous Mapuche were the first to cultivate these pale white berries, which they call kelleñ. In addition to eating them raw, the Mapuche dried them like raisins, prepared them in fermented chicha, and used them…