For years, I made peanut brittle for my father-on-law for every gift-giving holiday. He'd save and savor the candy, making it last until the next holiday. Then, a couple years ago, his doctor banned nuts and seeds. I scrambled for new ideas and made pretzel brittle and bacon brittle.
Then, as an experiment, I tried adding peanut butter directly to the brittle. Whole nuts and seeds had been banned, but peanut butter was just fine. I had no idea what the candy would be like, and I had no idea if he'd like it at all.
Much to my surprise, he said that it was just like a candy that he'd had as a kid, and he hadn't had it since. To me, it tasted sort of like the inside of a Butterfingers candy bar, with the peanut flavor and shattery texture.
But of course, when I made it the first time, it was an experiment, and I didn't bother to write down how I made it. Shortly after, he was able to eat nuts again, so I didn't need to worry about it. But this year, I decided to give it another try, it took a couple attempts before I managed to recreate the candy. This might not be my original version, but it's very peanutty and shattery and not as tooth-damaging as regular peanut brittle.
If you have a Silpat or similar silicon baking sheet, I've found that it's the perfect surface for the candy. Nothing sticks, and you don't need to butter a baking sheet and have buttered candy.
Use a candy thermometer or an instant-read thermometer that reads higher temperatures to monitor the temperature of the sugar mixture as it cooks.
Peanut Butter Shale
1 cup white sugar
1/2 cup light corn syrup
1/4 cup water
3/4 cup creamy peanut butter
1 teaspoon vanilla
1 teaspoon baking soda
Line a baking sheet with a Silpat, or butter the baking sheet.
In a medium heavy-bottomed pot, combine the water, sugar and corn syrup and bring to a boil.
Stir occasionally until the sugar melts, then stir more frequently until the mixture comes up to a temperature of 305 degrees.
Add the peanut butter, vanilla, and baking soda, and stir quickly to combine. The mixture will foam up. Pour immediately on the prepared pan, trying to spread it out evenly.
Allow the candy to cool completely, then break it into pieces.