I've made some tarts with frangipane and fruit. The pastry is flour, butter, icing sugar, egg yolk. Unfortunately they're only going to be eaten tomorrow. What's the best way to store them overnight to keep them nice and crisp? From experience if I keep them in a sealed box the pastry tends to go soft. Is there anything else I can do? Would they freeze - I'm worried the plums will go soggy when defrosted...?