Flavorful oranges are available all year long, but this tart is especially welcome in early winter, when there is little fresh fruit besides imports available. Lightly poaching the oranges controls the amount of juice that exudes from them during baking and makes for a neater and more intensely flavored tart. Almost any fruit can be adapted to this type of filling and crust. The upper tart in the photo is made with red-fleshed Cara Cara oranges. Blood oranges would be a flavorful and visually striking choice too. A couple of small and very sweet white or pink grapefruit would make a lovely tart, but don’t use the zest, which is too bitter.