Heat the butter and milk until the butter is melted. Set aside to cool to lukewarm.
In a large bowl, dissolve the yeast in the warm water. Let sit for 5 minutes to activate and then mix in egg yolks.
Blend in the cooled milk mixture and then sift in the flour, sugar and salt.
With dough hook, mix on medium speed until dough is soft and pliable.
Place dough in a large bowl that has been lightly sprayed with cooking spray. Cover with plastic wrap and refrigerate overnight or for about 8 hours. It will rise in the refrigerator.
After dough has been refrigerated, remove and tear in half. On parchment paper, roll out into a rectangular shape about 15 inches long and 8-9 inches wide.
Meanwhile, soften cream cheese and mix together until smooth with powdered sugar and milk.
Pour cream cheese mixture down the middle of the dough and spread out to two ends.
Use kitchen shears to cut strips in dough and braid in criss-cross fashion.
Preheat oven to 350 and bake for 18-25 minutes. This will vary depending on the type of baking sheet you are using. Pizza stones tend to be on the higher end of the baking time.