In a saucepan, on the stove over medium-high heat, combine blueberries, granulated sugar, light brown sugar, cornstarch, ground cinnamon, and ground nutmeg. Stir occasionally for 5 minutes, or until the fruit mixture has thickened to the consistency of jam.
In a large mixing bowl, using a hand mixer, beat cream cheese and powdered sugar until fluffy, approximately 1 minute.
Split biscuits in half to form 16 dough circles. Arrange 8 of them on a parchment-lined baking sheet with about 2 inches of space between them.
Spoon 1 tablespoon of cream cheese onto each biscuit. Spoon 1 tablespoon of blueberry filling on top of cream cheese. Top each with the remaining halves of biscuit dough. Crimp and seal edges with a fork. Any remaining filling can be used for dipping when serving.
Bake according to directions on Pillsbury Grands Biscuit can (usually 13-16 minutes).
Once biscuits are golden brown, melt butter in the microwave, and using a basting brush, brush the tops of the biscuits.