Recipe:
Step 1. Cut desired number of fruits lengthwise and juice them, or accumulate the undamaged peels of fruits that you have eaten in a container in the fridge. Unless you want your end product to be complete halves, cut peels into quarters to prevent them from breaking up in step 2. Keep different types of citrus fruit separate. Note that three 2L icecream containers of fresh peel yields one 'cookie time' barrel plus one 500g honey jar of candied peel strips.
Step 2. Place peels in cold water in a covered saucepan, bring to the boil, turn off the element, and leave to stand at least 30 minutes. Discard the water and repeat once for orange rind, twice for lemon or grapefruit rind. You can use the water to water acid-loving plants like citrus and passionfruit, or simply throw it away. This boiling softens the skins and gets rid of their bitterness.
Step 3. Scrape any remnants of flesh and the white pith and stringy bits off the rind and cut each piece into two or three pieces so that they pack better into the saucepan. Treat them carefully as they tear easily at this stage.
Step 4. Mix equal volumes of sugar and water and boil to the thread stage (108 degrees). This takes about 45 min - if you're using a sugar thermometer be aware that the temperature rises quickly after about 105 degrees, so keep a good eye on it after that. I usually use 3 cups each of sugar and water to make the syrup - how much you will use depends on the size of the pot you will use for crystallising.
Step 5. Place peels and hot syrup in a preheated crockpot and leave on high until transparent (2 - 3 hours), or simmer them together on the stove the same time. You can't really overdo this stage unless you leave them for many, many hours, so don't worry if you can't get to them straight after three hours!
Step 6. Drain the peels and allow to cool till you can handle them, then slice into strips if desired (I usually do this, unless I'm wanting to use bigger pieces to decorate a cake or something) and dry on cooling racks in the oven at 80 degrees for about 12 hours. They are done when they are no longer tacky but still flexible.
Step 7. Coat in castor sugar or dip in chocolate (100g chocolate does 60-70 8mm wide strips) before eating as a sweet, or chop to use in baking.
Store in an airtight container at room temperature.
Candied peels keep at least 1 year. They are good to eat as is, chocolate coated or chopped up in cakes, biscuits, breads and bread puddings. The left-over syrup can be reboiled and used up to four times (adding an extra cup of sugar every second time or so), but eventually it will become too tart to be pleasant. You can also use leftover syrup as an icecream/pancake topping (boiling it to 115-120 deg C will give it the consistency of treacle - as it it's pretty thin) or boil it down to make toffee (add extra sugar and 1T butter per cup extra sugar and boil to 150 degrees - 30-45 min).
Variation:
Slice thin slices of whole orange then candy in syrup (don't preboil slices) to make candied orange slices. If you try this with lemons, they will taste nice but will go an unattractive reddish brown.
Candy ginger by steaming it in chunks or matchsticks as desired then candy in syrup. Pack into hot jars with syrup while still hot and seal, or dry as for peel. The syrup makes a nice addition to stir-fry dishes.