Marble Top Fudge

Why I Love This Recipe
For best results do not double this recipe.
Ingredients You'll Need
3 cups semisweet chocolate chips (1 1/2 packages, 12 ounces each)
4 tablespoon unsalted butter divided
1 can sweetened condensed milk (14 oz - not evaporated milk)
1 1/2 teaspoon vanilla
dash salt
1/2 cup chopped walnuts
2 cups miniature marshmallows
Directions
Line 8 or 9 inch pan with foil
Melt chocolate chips and 2 tablespoons butter with sweetened condensed milk, vanilla and salt in heavy saucepan over low heat. Remove from heat; stir in nuts. Spread evenly into prepared pan.
Melt marshmallows with remaining 2 tablespoons butter in medium saucepan over low heat. Spoon into fudge. With table knife or metal spatula, swirl through fudge.
Refrigerate 2 hours or until firm. Remove fudge from pan; peel off foil. Cut into squares. Store loosely covered at room temperature.