Making candied orange peel is easy once you learn what to watch for. Expect a couple of spoiled batches where you undercook or burn the product, but after that it’s straightforward.
The number of oranges to use is hard to specify. I eat two oranges a day and save the peel. Since I want as many long 1/4 to 3/8 inch wide strips that are 2 inches long, I cut the oranges in half and juice them or quarter them and carve out the inside (and eat it). Then I wash the peels under running water, and scrape as much of the meat off as I can and then toss the peels into a sealed plastic bin I have in the refrigerator. The sealed bin has a small amount of water on the bottom to keep them hydrated, otherwise the refrigerator will dry them out and they’ll shrivel.
When I have “enough”, I get the cutting board and start slicing as many long pieces as I can and I dice up the odd pieces, and continue until I have enough to fill a small 16 cm stainless saucepan about 3/4 full (but not more).
Next, the peels optionally get boiled in the saucepan. Boiling them like I describe here will reduce the flavor and remove bitterness. It will also help to hydrate any peels that have dried and thinned. You can skip the boiling steps here for a stronger orange flavor. If I’m going to use the peels for baking I skip the boiling to get a stronger flavor. To boil the peels, fill the saucepan with water, and boil for 10 minutes or more, dump them into a strainer and hit them with cold water. Then back in the pot to boil again for 10 minutes or so, dump and rinse with cold water.
Next comes the candying step. Put 2 to 2-1/2 cups of sugar in the saucepan and 1 cup of water, bring it to a boil and dissolve all the sugar. Be careful from here on because the sugar syrup will be at 240 degrees F. Treat it with respect because it WILL hurt you–think napalm. Gently add the peels to the boiling syrup, bring back to a boil, then reduce to medium heat and cook them in the syrup (uncovered). I’ve seen recipes that say to cook for 20 minutes. Forget that. It takes 40 to 45 minutes of cooking. The whole time it will be merrily bubbling and foaming. Stir occasionally to make sure nothing is sticking or burning. When you get to around 40 minutes, you’ll notice the amount of liquid is getting less and less and now is where you really have to pay attention. You want the peels to get that “glassy” candied look–not all the way through, but you want to see the flesh start to get glassy. Some people say to boil until all the syrup is gone. If you do that, you’ll burn the peels. There’s a fine line where they are “just right” and it always seems to come at around 45 minutes.
While it’s cooking, I put out sheets of waxed or parchment paper. When the decision point comes, dump the contents of the pot into a metal screen strainer (remember it’s at 240F which will melt some plastics) and let it drain for a minute. Then spoon them out onto the waxed paper and as quickly as you can spread them out so they are touching each other as little as possible. When they cool they will stick together. It’s pretty easy to unstick them from the paper but not from each other. Then let them cool off and dry for a while, an hour or two, and then you can use them or cover with another sheet of waxed paper. You can stack several batches on top of each other and store them like this for several days.
Finally, you can sprinkle them with flour and mix them into a cake. You can dip the long ones in melted chocolate (just like strawberries). You can coat them with powdered sugar, use then to garnish ice cream, whatever.
To try this out I’d recommend starting with four oranges worth of peel. The thickness of orange peels varies a lot so it’s hard to say how many oranges you need. Thick skinned oranges are great for this application. Oranges with very thin skins are not good choices for candying. You can also do this with grapefruit skins for a very different flavor.
For me, candied orange peel is one of the greatest flavors on earth, and it’s extra fun to make because you are using what would otherwise be garbage plus about 20 cents worth of sugar. However, it is labor and time intensive.