Butterscotch Fudge

1 teaspoon plus 2 tablespoons butter (no substitutes), divided
1 2/3 cups sugar
2/3 cup evaporated milk
1/2 teaspoon salt
2 cups miniature marshmallows
1 package (10 to 11 ounces) butterscotch chips
1/2 cup chopped walnuts
1 teaspoon maple flavoring

Line an 8-inches square pan with foil and grease the foil with 1 teaspoon butter; set aside. In a saucepan, combine the sugar, milk, salt and remaining butter; cook and stir over medium heat until mixture comes to a boil. Boil for 5 minutes, stirring constantly. Remove from the heat; add marshmallows, chips, nuts and maple flavoring. Stir until marshmallows and chips are melted. Spoon into prepare pan. Let stand until set. Using foil, lift fudge out of pan. Discard foil; cut fudge into 1-inch squares. Store in an airtight container at room temperature.