1In large saucepan, simmer beer over medium heat 10 minutes, stirring occasionally. Stir in butter and brown sugar. Cook about 12 minutes, without stirring, to 234-235°F on candy thermometer (mixture will look syrupy).
2Remove from heat. Slowly add whipping cream, vanilla and salt, stirring constantly. Return to medium heat; cook 3 to 5 minutes, stirring occasionally, until thickened and creamy. Cool 2 hours.
3To serve, scoop ice cream into 6 glasses or bowls. Top with walnuts and whipped cream topping. Drizzle with caramel sauce. Refrigerate any remaining caramel sauce.