Ground dried orange peel and ground rosebuds (see Note), optional
In an electric slow-cooker or a shallow 3-quart baking dish, combine the sugar, cloves, and lemon juice with 1⅓cups water. Stir to dissolve the sugar.
Wash the quinces; peel, halve, and remove the cores, reserving all trimmings. Place the peels, cores, and quince halves in the slow cooker or baking dish. Cover and cook on low or bake in a 250°F oven for 5 to 7 hours, until the fruit turns creamy pink. Turn off the heat and let cool before uncovering. (This allows the quince to re-absorb more of the syrup.)
Use a slotted spoon to transfer the quince halves to a wide container. Strain the cooking liquid and boil it down to 1 cup. Pour over the quince. Store covered in the refrigerator. (Discard the peels and cores.)
Serve the quince well chilled, with dollops of clotted cream, drained yogurt, or crème fraîche. Decorate with chopped toasted almonds. If desired, dust lightly with ground dried orange peel and rosebuds.