Unmolding bundt cakes intact can be difficult, especially with these newfangled pans with lots of intricate details. Here are some pointers:
Regardless of what your recipe tells you, it’s best to allow your cake to cool for at least half an hour before you attempt to unmold it. No bundt pan is truly non-stick, no matter what its coating. It’s important to grease and flour your pan extremely well, reaching into every nook and cranny of the design. Chowhounds recommend using a pastry brush to coat the inside of the pan liberally with shortening or melted butter, then dumping in a good amount of flour (or cocoa, if you’re baking a chocolate cake) and shaking it around until you’re sure it has coated every surface of the pan–then tap the extra out into the trash. Alternately, use a very generous coating–no simple spritz–of Baker’s Joy or Pam for Baking (oil sprays with flour incorporated), which also release cakes from fancy bundt pans beautifully.