Xavier Canal, the favorite baker of Barcelona’s smart set, is a great master of apple tarts. In this one, he fills a crumbly tart shell with pine nut and almond custard and tops it with diced apples briefly cooked in rosemary syrup. The rosemary accent is faint but intriguing; if you want to intensify the herbal flavor, add a little finely minced rosemary to the apples. Once you’ve made this version, Xavier suggests trying a
