Easy solution? Silicone muffin cups or baking pans. Use the muffin cups - in either grand, regular or mini size - on top of regular sturdy cookie sheets. You don't even need to grease the muffin cups beforehand, and still you'll be able to slide out your baking delights with no worries!
Or, even easier, invest in a high grade silicone muffin pan and you won't even need to use a cookie sheet underneath. Either way, your muffins will look perfect and intact - not misshapen and embarrassing!
Or...for the cutest silicone muffin cups EVER, check out these little lovelies by Wilton - Silly Feet Silicone cupcake holders with silly silicone feet! They're adorable and a surefire hit with kids of all ages.