Cheesecakes and custard-based pies are prone to condensation, especially if you don't let them cool completely before wrapping and chilling. There is however and elegant solution involving a not so elegant item, and that item is toilet paper.
Photo by Susanne Nilsson.
Look, I know what you guys are going to say, but just hang in there for a moment. As long as you use a roll that has never seen the inside of a bathroom, there is no issue here; you're just working with a roll of cellulose that has been processed into delicate, thin sheets, perfect for blotting the tops of certain desserts. As Alice Medrich explains in the article below, paper towels are not only too coarse, but they often have embossed patterns that can leave an impression on your cake or pie. Using TP in this way is a pretty simple process, but it does require a delicate touch:
Simply lay pieces of toilet paper directly on the surface of the cake -- don't dab or wipe -- and sweep your fingers very lightly over the paper to absorb as much moisture as possible. Lift the paper and repeat with more dry pieces of paper as necessary.
Also, I would recommend the super cheap stuff for this. Premium, super soft toilet paper can be linty, and fluffy lint has no place on a cheesecake.