In a large bowl, cream the butter and shortening with an electric mixer until well blended. It should have a light and fluffy consistency.

Add vanilla and milk, mixing well.

Slowly add 3 cups of powdered sugar, a little at a time. Continue to mix as you keep adding more. The frosting should be soft but hold its shape in stiff peaks. If needed, you can add up to one more cup of sugar to get the desired texture. Set frosting aside.

Using a bread knife, trim about 1 1/2 inch off the open end of each ice cream cone to make it slightly shorter. It works best when you score all the way around, then snap the cone off.

Place a piece of wax or parchment paper on your table or counter top.

In the bowl of a double boiler, melt the red candy melts over medium heat. If necessary, add 1-2 tablespoons of shortening to create a smooth texture.

Once candy melts are completely melted, roll the cones in it until the outside is completely covered. Place them on the prepared wax paper or wire rack to set.

Place your sanding sugar or white sprinkles in a shallow dish.

Fit a pastry bag with a round tip (or just cut the tip off the bag) and fill with frosting. Pipe frosting onto the cupcakes.

Gently dip the frosted cupcakes into the sanding sugar.

Next, place a marshmallow on a toothpick or bamboo skewer. Coat the marshmallow with frosting, then dip it into the sanding sugar or sprinkles. This will be the pom pom for the Santa hat.

Squeeze a small dot of frosting onto the tip of the ice cream cone and gently press the marshmallow into place. Repeat with remaining cones.

Finally, place cones on the frosted cupcakes and gently press down to secure in place.