Chocolate snowswirl fudge recipe in the fudge category

: Melt chips with sweetened condensed milk, 2 tablespoons of the butter, vanilla extract and salt. Remove from heat. Stir in nuts. Spread evenly into foil lined 8 or 9 inch square pan. Melt marshmallows with remaining 2 tablespoons butter. Spread on top of fudge. With table knife or metal spatula, swirl through top of fudge. Chill at least 2 hours or until firm. Turn fudge onto cutting board. Peel off foil and cut into squares. Store loosely covered at room temperature.