In the interest of decreasing waste and using everything, candied peels. It's pretty simple. Three ingredients: sugar, water, peels. In addition to candy and an ingredient for baking, there will be syrup for drinks and flavored sugar.
Eat the fruit, trim the peels, place in a pot of cold water. Bring to a boil. Drain.
Return to the pot. Add equal parts sugar and water. Simmer until translucent.
Strain the syrup into a clean jar.
A tea strainer and a wide mouth funnel make it easier.
The syrup is tart and tasty. Grapefruit soda or add gin for a Grapefruit Tom Collins. Soak a cake. A base for granita. Use your imagination.
Dry on racks set in trays (parchment lined trays for easy cleanup) until desired consistency. For fruit slices type candy, dry until soft and sticky, then coat with sugar. For batons that may be dipped in chocolate, wait until firm and slightly tacky. It was humid in my kitchen: soft = 1 day, firm = 3 days.
Grapefruit batons, tossed with sugar for storage. The sugar left behind is great to sprinkle on baked goods, dress the rim of a glass.
Serve as is, dip in chocolate, use as you would candied orange or lemon peel. Very nice as a garnish for mixed drinks.