Quince

Quinces, fruit of the central Asian tree Cydonia oblonga, give us a taste of what apples and pears might have been like in their primitive form. They are gritty with stone cells, astringent, and hard even when ripe. But they have a distinctive, flowery aroma (thanks to lactones and violet-like ionones, all derived from carotenoid molecules) that’s especially concentrated in the fuzzy yellow skin. And cooking domesticates them: heat breaks down and softens their pectin-rich cell walls, and the astringent tannins become bound up in the debris, so the taste softens as well. Quince paste firm enough to slice is a traditional product of Spain (membrillo) and Italy (cotognata), and in Portugal a quince preserve was the original marmalade (marmalada). The 16th-century alchemist and confectioner Nostradamus gave several recipes for quince preserves and observed that cooks “who peel them [before cooking] don’t know why they do this, for the skin augments the odor.” (The same is true for apples.)