I made some little tarts out of last year's left-over marzipan, we called them "sweetie-pies" and my children loved them.
Cut shortcrust pastry into rounds and put into tin as if for jam tarts/mince pies.
Blitz up marzipan with egg white (prob. one medium egg white to about 100g marzipan), you could do it with a blender but I blended it with my fingers and then whipped it with a fork)
Whip some double cream into it (about 1tbsp per 100g marzipan)
Add 2 tbsps icing sugar and a few drops vanilla extract and mix - it should be a paste, like smooth peanut butter - if not, add more sugar until it is.
Put a blob of seedless jam (homemade plum is good and christmassy!) into the bottom of each tart and spread a bit.
Sprinkle/grate a bit of nutmeg onto the jam.
Spoon the marzipan mixture into the tarts, about as much filling as you would give a mince pie.
Bake on about 200C ( depending on your oven!) for about 20 minutes. When they are ready to come out thy should look puffed up and browned on top. They will sink a bit but not completely when removed. Allow them to cool.
Very nice with brandy butter/extra thick cream!