Lately I have been experimenting with sweet potatoes. My current recipe for making them uses two main ingredients: the potatoes themselves and caramel. The first step is to cook the potatoes in an oven. I use my convection toaster oven set to 350 or so and leave them in for an hour… ish. Make sure that you poke holes in the potatoes you really don’t want those suckers to explode in your oven. I’ve had that happen and its not pretty.
While the potatoes are cooking, make the caramel. At its most basic level all it really involves is to toast some sugar and pour some heavy cream in to smooth it out. But there are multiple ways of doing this. I usually do the dry method. Which is to pour sugar into a nonstick skillet and heat it until it liquefies and turns brown. But this method is prone to scorching. Another way is the wet method. Add water to the sugar and boil it until the water evaporates. By then, the sugar will have melted and you can continue boiling until the sugar caramelizes nicely. But this method has a risk of crystals forming. You have to babysit the pan and wet or grease the sides down to discourage crystallization.
I tried a new method recommended by one of my favorite cookbook authors: Shirley Corriher. This is to use a microwave. To prevent crystals from forming, Corriher explains that the substance must be impure. The impurities that you can add to the caramel come in different forms of sugar. Table sugar is a double sugar which consists of fructose and glucose that are joined together. By adding corn syrup (mostly glucose) and by adding lemon juice (an acid which cuts the sugar into fructose and glucose), you have a mixture of three kinds of sugar. These molecules are different enough to prevent crystallization.
In a microwave safe pyrex bowl, add 1 cup of sugar, 1/2 cup of corn syrup, and 10 drops of lemon juice. Thoroughly mix together (adding a little bit of water if needed). Microwave on high for a couple of minutes until the mixture starts bubbling. Now, closely watch it until it turns light brown. When it does, turn off the microwave! Carryover cooking will continue to brown the mixture. Keep in mind that this liquid sugar is close to 250 degrees Fahrenheit.
Next add heavy whipping cream. But this time I used evaporated whole milk. This is by far the hardest part. In a saucepan, boil the cream (or evaporated milk). Pour the still molten sugar in and step back. That cream will bubble furiously! And the sugar will instantly harden rock solid. Turn off the heat and stir the mixture. Eventually, if you work hard enough, the sugar will melt back into the liquid. Also be aware that if you use water rather than cream or milk that you are creating an exothermic reaction. The mixture will actually heat up. And another thing to keep in mind, perhaps the most important thing, is that the stages of sugar cooking are rather thin. The firm ball stage of sugar syrup is from 244 to 248 degrees Fahrenheit. Not a very large margin of error.
You can make the caramel ahead of time. And you can let the potatoes cool down for a while. Or even cook them ahead of time as well. All you need to do is to whip up the potatoes and add whatever amount of caramel you want. And if you are A. R. enough, you can strain the sweet potatoes through a food mill to help reduce the stringy fibers. Don’t forget to add salt and pepper while you mix it…
The final result is a medley of roasted notes. The roasted sugars in the potatoes, the roasted sugar in the caramel, and the roasted milk sugars from the evaporated milk.
