undercooking, so it doesn't set up; scorching; or the dreaded "separation," where the butter and sugar separate during cooking.
If this occurs, you'll see an oily layer on the surface of your candy mixture, "and it looks sooooo ugly, like an oil slick," is how Kendrick describes it.
A psychologist might just chalk it up to "separation anxiety." Some candy experts theorize that it's due to an abrupt temperature shift, or from not stirring the mixture enough during cooking, or from using a too-thin saucepan that doesn't conduct heat evenly, or too much humidity in your kitchen.
Kendrick says the trick is to mix the sugar and butter together over low heat to make sure there are no sugar crystals in the mixture, then turning it up to medium-high to finish cooking.
"I think the secret is starting out slowly and getting all the sugar dissolved," she said. "Then turn up the heat, stir it constantly and get it done fast. It works for me this way, so I'm going to keep doing it this way."
And Kendrick should know. She won the Utah Chocolate Show's toffee competition and was named the Utah Chocolate Champion for winning the most categories of chocolate confections. She also recently completed 2,000 pounds of toffee for a client, "and we didn't have a single failure," she said.
• She uses salted butter (instead of unsalted) so she doesn't have to add salt to the recipe. "Some people say to start with butter at room temperature or frozen," she said. "I've done it with both, and it all works. I've had trouble with certain butters, but this year I used Costco's Kirkland brand, and I'm as happy as can be with it." But be sure it's real butter, not margarine or a "spread" with extra water and fillers.
• Rub the cube of butter around the sides of the pan before adding sugar. This will help keep sugar crystals from clinging to the sides.
• When adding the sugar, place it in the center of the pan to keep sugar crystals off the pan sides.
• During cooking, occasionally wash the sides of the pan with a brush dipped in water.
• Keep stirring the mixture as it cooks. This is especially critical toward the end, to make sure it doesn't scorch on the bottom.
• When the sugar is fully dissolved, which may take about 10 minutes, you can turn up the heat to medium-high.
• During cooking, the mixture will darken to a golden brown. This is the point where it could separate. If it does, try adding a tablespoon or two of water and keep stirring, Kendrick advised. Sometimes you can get the mixture back together.
• Kendrick said she cooks her toffee a little darker than most. Generally, it should be around 285-290 degrees for Utah altitudes. Keep in mind that this is about 8 degrees lower than what most cookbooks specify, because they are written for sea level. This would be hard-crack stage for those doing the cold water test. However, by the time you've put a few drops of the syrup in cold water to see if they crack, the temperature has likely increased by several degrees.
• Another visual clue for doneness: A puff of smoke will come off the candy.
• You don't need to butter the pan before pouring the toffee into it. Just cover the pan with a thick bed of nuts, and pour the toffee over the nuts. The nuts will allow it to release from the pan when it's cool. Any nuts left in the pan can be re-used for the next batch of toffee.