The flesh, rind and seeds of kumquats are edible. Although the preserves are delicious on their own as a simple dessert, you can serve them as an accompaniment to fruit sorbet or use them to enliven a compote of fresh oranges.
Nutrition per serving may change if servings are adjusted.
2 pounds firm kumquats
2 cups sugar
4 cups water
1 cup brandy
2 vanilla beans, split lengthwise
Thoroughly scrub kumquats with warm water. Trim stem ends. To prevent the kumquats from bursting during cooking, pierce them with the point of a sharp knife in several places. Place the kumquats in a medium saucepan and cover with water. Bring to a boil over medium heat and blanch for 1 minute. Drain and set aside.
Combine sugar and 4 cups water in a medium saucepan. Bring to a boil over low heat, stirring occasionally until the sugar dissolves. Add the blanched kumquats, return the liquid to a simmer, and cook for 10 minutes.
Remove the kumquats from the syrup with a slotted spoon and divided among four 1-pint sterilized preserving jars. Add 1/4 cup brandy to each jar, then pour in enough of the hot syrup to fill the jars, leaving 1/2 inch of headspace. Tuck a vanilla bean half into each jar and close the lid.
Make Ahead Tip: Store the jars in the refrigerator for up to 3 weeks.