Starbucks can kiss my pumpkin

I have a weakness for the Starbuck's Pumpkin muffin.  You know the one with the cream cheese in the middle...yeah...that's the one.  They are only around for a few weeks in the fall, and I could eat one everyday that they are available.  Sadly, that gets a little expensive.  When I saw a recipe for a cream cheese filled pumpkin muffin on Annie Eats, I was pretty much sold. 

A few thoughts...

It is really very hard to shape beaten cream cheese into a log.  When I think log, I think round....think more like brick.  Also, don't scrimp on the freezing cream cheese part.  I only left mine in the freezer for about an hour and that was no where near long enough.

Finally, this recipe uses oil as the fat.  I generally prefer to use butter in my baking. (Who doesn't like butter?)  I'm wondering what anyone out there thinks about substituting butter for oil.  Is it a one to one substitution?  Do you need to account for extra water in the butter?  Thoughts?