This is a short post about a big area: candied fruit. It's short because I can't improve on, nor claim as my own, these instructions for the basic two-week process of candying fruit. That said, there are many ways to do it, and if some other method sounds better to you, go for it.
I've been candying fruit for years, and not to toot my own horn, but I play around with it more than I have seen others do. So these are my comments on it in general:
1: Citrus performs terrifically. Berries don't. Apples, pears, and quince don't -- they become all sweetness with no flavor. The basic process here replaces all of the water in the fruit with a very rich sugar syrup, which makes for a very sweet product, and not all flavors stand up to that. Pineapple and cherries are the best non-citrus options. I kinda think it's not coincidence that the typical mix of fruit in a fruitcake is ... citrus, pineapple, and cherry.
2: Chile peppers perform very well. I've made several "tropical boomcakes" -- fruitcakes flavored with slices of candied habanero and pineapple, rum, ginger, and cinnamon. Using habanero, it's not hard to make a fruitcake that's spicier than any commercial product this side of hot sauce. But jalapeno and other chiles have great flavors that go well with sweetness. Last year I made "jalapeno poppers," using candied whole jalapenos, filled with a ganache of caramelized white chocolate and Seville orange rind.
3: There is no reason the syrup cannot have flavor in it.
That's what I mean by doing more than I've seen other people do. It started with saffron-flavored candied pineapple, when I was first experimenting with sweet applications of saffron five years ago (best results: saffron/vanilla bean ice cream, or saffron dulche de leche baked into the top of brownies). I've used ginger in the syrup for candying habanero, and made a reasonable jar of sugar plums using "Christmas spices" to flavor small candied plums.
The above photo is of two examples: a lemon slice candied with tea infused syrup, which will probably find its way into a lemonade cake; and my pride and joy, the Coca Cola cherry.
Imagine the cherry orchard behind Willy Wonka's chocolate factory, some years after its acquisition by the Coca-Cola Company. You pick a fresh, tart, Balaton cherry, and take a bite. It tastes like Cherry Coke, but -- not quite. Because the cherry element, the fruit flavor, tastes not like Hubba Bubba bubblegum but like a real, fresh cherry -- and somehow all the Coca-Cola flavor is there too.
It's pretty fucking great. I just used Coca-Cola fountain syrup as my candying syrup, and boosted it with sugar until the cherries became candied. Think of the soda that the leftover syrup will make!
You can also make very simple "sour patch" candies by taking candied fruit that has been taken out of the syrup and left to dry some, and then rolling it in a combination of granulated sugar and citric acid.
There's a lot of potential down this road.