These are the simplest things in the world to make!
Take some ice-cream cones and fill with chocolate buttons/jelly-beans/M&M's, etc.
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Then take some green icing and seal the bottom with a plain, round biscuit.
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Coat the whole cone with icing and decorate with dragees, or roll in sprinkles.
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Sandwich two oreos together with a little icing. And with a little more icing on the top, attach the cone to the top.
Voila! Iced Christmas trees!