Preparation Stir sugar and bourbon in heavy medium saucepan over low heat until sugar dissolves. Increase heat to medium-high. Boil without stirring until mixture turns deep amber color, brushing down sides of pan with wet pastry brush and swirling pan occasionally, about 8 minutes. Remove from heat. Add cream (mixture will bubble up) and whisk until smooth. Return to boil, whisking constantly. Remove from heat, add butter and chocolate and stir until smooth. Mix in nuts. (Can be made 1 week ahead. Cover and chill. Before using, rewarm over low heat, stirring constantly and thinning with small amount of water if necessary.) Serve ice cream with sauce.
Preparation Stir sugar and bourbon in heavy medium saucepan over low heat until sugar dissolves. Increase heat to medium-high. Boil without stirring until mixture turns deep amber color, brushing down sides of pan with wet pastry brush and swirling pan occasionally, about 8 minutes. Remove from heat. Add cream (mixture will bubble up) and whisk until smooth. Return to boil, whisking constantly. Remove from heat, add butter and chocolate and stir until smooth. Mix in nuts. (Can be made 1 week ahead. Cover and chill. Before using, rewarm over low heat, stirring constantly and thinning with small amount of water if necessary.) Serve ice cream with sauce.