This crunchy almond brittle is sometimes enjoyed in the south of France as part of "Treize Desserts," a Christmas Eve tradition of serving thirteen sweets, representing Jesus and the twelve apostles.
Brush a 9-by-13-inch rimmed baking sheet with butter; set aside. Combine sugar and corn syrup in a saucepan. Bring to a boil, stirring until sugar has dissolved. Using a pastry brush dipped in water, brush away any sugar crystals on side of pan to prevent recrystallization. Cook, swirling occasionally, until mixture reaches soft-ball stage on a candy thermometer (238 degrees).
Stir in almonds; cook, stirring occasionally, until mixture is light amber in color.
Pour mixture onto prepared baking sheet; spread quickly into a 1/4-inch-thick layer with an oiled metal spatula. Let sit 2 minutes before cutting, if desired, with a sharp, oiled knife. (Or let cool completely before breaking into pieces.) Set sheet aside until completely cool. Store in an airtight container at room temperature for up to 1 month.
Tomake Sesame Seed Crunch,substitute 11/2cupstoasted sesame seeds forthe blanched almonds. Stir in 2teaspoons offreshly squeezed lemon juice before pouringthe mixture onto the prepared sheet.