Place a layer of paper towels on a large plate. Spread a full 15 oz. can of pumpkin puree on the paper towels. Top the pumpkin with another layer of paper towels. After 15 minutes, gather the paper towels and squeeze as much of the liquid as possible from the pumpkin puree.
In a large mixing bowl, whisk the melted and cooled butter and sugars together for one minute. Whisk in the egg yolk, vanilla extract and pumpkin puree until smooth and well combined. Mix the dry ingredients into the wet until just combined.