Preheat oven to 375 degrees F.
Dice mushrooms into small pieces.
In a skillet, heat olive oil over medium high heat.
Add garlic and shallot, cook for 1-2 minutes.
Add in diced mushrooms, stir to mix.
Cook mushrooms for 3 minutes, stirring frequently.
Combine balsamic vinegar and brown sugar in a small bowl or measuring cup.
Add balsamic mixture to mushrooms.
Cook until liquid dissolves and becomes a glaze, about 5 minutes.
Lay out one package of phyllo sheets, cut in half along the fold. (there may be two packs per box)
Set one half aside (if you are careful you will not need it and may be able to save for another time)
Take 1 phyllo square and brush lightly with melted butter.
Place a second phyllo sheet on top of the first and brush with melted butter.
Repeat until you have four sheets stacked. (you do not need to butter the 4th sheet)
Cute this phyllo stack into 4 equal squares.
In the center of each square place 1/2-1 tablespoon of mushrooms, and 1/2 -1 tablespoon of cheese.
Gently gather the edges of the phyllo around the filling and gathering in at the top, pinching the phyllo closed.
Repeat steps until you have made about 20 bundles.
Place bundles on a greased baking sheet and bake for 20 minutes or until golden.