Heat the oven to 400ºF/200ºC. Butter the molds well.
Dust a sheet of thawed puff pastry with 1 tablespoon sifted powdered (icing) sugar then cut into strips - between ⅓ to ½ inch or 1cm thick.
Fold the pastry over the end of the mold wind the pastry around the mould overlapping slightly. One strip will not reach the top of the mold and these will make a bite size pastry. But you can add more strips to make large cream horns.
Place on a baking paper lined baking tray with the end of the pastry down so that it doesn't pop up during baking. Brush lightly with milk.
Bake for 10-15 minutes until crisp and lightly browned.
Remove and cool until ready to fill.
To fill cream horns
Using a teaspoon place a small amount of jam in the bottom of the pastry horn. Then fill with buttercream, whipped cream or Italian pastry cream using a piping bag.
Finish off with a half a raspberry and dust the cream horns with extra sifted powdered (icing) sugar.
Old fashion buttercream (optional)
This will make lots of buttercream but any left over can be used to ice cakes or cupcakes or frozen for later use.
Mix powdered gelatine with 1/4 cup water, stand 5 minutes then heat gently to dissolve.
Allow it to cool to room temperature.
Beat unsalted butter and superfine sugar until light and creamy.
Very gradually add the dissolved gelatine mixture.
Once this is incorporated gradually add the cold water and cream of tartar, if using. By this stage the cream should be white and fluffy.
Make ahead and refrigerate until required. The cream will need to be removed from the refrigerator for a few hours to allow it to soften to a creamy consistency. The time this will take will depend on your climate.