White or raw sugar
Citrus peel, some cut with a peeler and some with a zester (Peeling very thinly, remove most of the white pith left, much of this pith will cause a bitterness to the finished product. Spread the peel out in a single layer, white part up, letting it set out on the counter for a day in the air at room temperature to dry. Drying thoroughly is not necessary, but removing some of the moisture and not using it 'fresh off the fruit' is very important.)
Clear jars, (with tops) such as mason jars
Fill jars with sugar to a depth of 1/2-inch. Add some of the citrus peel then cover with another layer of sugar. Continue in this way, ending with the sugar about 1/4-inch from the top of the jar. Replace lid. Allow to sit for a few days so the citrus flavor infuses the sugar.