Step 1Line a rimmed cookie sheet with aluminum foil and grease lightly with cooking spray.
Step 2In a large, heavy-bottom saucepan, combine the beer, sugar and corn syrup. Bring the mixture to a boil over high heat, then reduce the heat to maintain a good simmer (watch that the mixture does not boil over, stirring occasionally if needed). Cook until a candy thermometer inserted reads 310 degrees, then remove from heat.
Step 3Immediately stir in the salt, vanilla and nuts. Be careful, as the mixture will steam. Quickly pour the brittle over the pan, spreading it thin. Cool the brittle, then break into pieces.