Grease an 8-inch round cake pan with softened butter. Pour the chocolate and butterscotch chips, condensed milk and vanilla into a medium saucepan. Put the pan on the stove and turn the heat to low.
Cover the empty condensed-milk can with plastic wrap and put it in the center of the round cake pan.
Stir the chips and milk until they melt together, about 3 minutes. Have a GH (Grown-up Helper) move the pan off the stove if its too heavy. Place the pan on a pot holder so it does not burn the kitchen counter. Stir in the nuts and raisins. Scoop the fudge into the cake pan all around the plastic-covered can in the center to form a wreath or ring shape. Let it be all bumpy and funky on top. Keep pushing the can back to the center if the fudge moves it away from there. Cut the red cherries in half with scissors and the green cherries into quarters. Use the green pieces to make leaves and the red to make holly berries. Decorate the fudge with several groups of holly berry sprigs made from the cherries and garnish with walnuts between the sprigs. (The fudge looks good left plain, too!)
Put the fudge in the fridge and chill until firm. Remove the can from the center, then loosen the sides and bottom of the fudge with a spatula. Cut the fudge into thin slices to serve.