1. Spread walnuts on a baking sheet and bake for five minutes.2. Combine butter, sugar, and evaporated milk in a heavy-bottomed saucepan. Bring to a boil over medium heat, stirring frequently.
3. Remove from heat and stir in white chocolate chips, marshmallow creme, maple extract, and toasted walnuts.
4. Pour into prepared dish. Let cool completely before cutting into squares.