1 tablespoon unsalted butter, plus more for pan
2 1/2 cups (12 ounces) dry-roasted, salted peanuts
1 cup sugar
1 cup light corn syrup
1 tablespoon baking soda
1. Butter a large baking pan; set aside. Combine peanuts, sugar, and corn syrup in a medium saucepan. Set over medium-high heat, and bring to a boil, stirring constantly.
2. Insert a candy thermometer. Continue boiling, without stirring, until temperature registers 295�, about 6 minutes. When sugar begins to brown, stir nuts gently to ensure even cooking. Remove saucepan from heat, and stir in the butter and baking soda; the mixture will begin to foam up, so mix quickly. Pour onto the prepared baking pan.
3. As soon as candy is cool enough to handle, use your fingers to stretch the brittle as thinly as possible over the baking pan. Allow the brittle to cool completely, about 45 minutes, then break into bite-size pieces. Store in an airtight container up to 2 weeks.
Makes 1 1/2 pounds
Foods with a high sugar content, such as peanut brittle, tend to draw moisture from the air, so try to make this candy when the weather is sunny and dry rather than humid or rainy.