Step 1

First, preheat oven to 400°F. Then, in a large skillet, heat butter over medium heat. Add chopped fresh mushrooms and onions and cook and stir until tender, or about three to five minutes. Add garlic and pepper; cook for an additional minute. Stir in cream cheese until melted and combined; remove from heat.

Step 2

Unfold one pastry sheet and cut it into nine squares. Next, cut each square diagonally in half. Place a teaspoon or so of the filling on one side of each triangle, being sure not to get too close to the edges. Then, brush the edges of the non-filled side with water; fold the pastry over the filling to form a triangle. Seal edges with a fork; place about an inch apart on parchment-lined baking sheets. Repeat with the second pastry sheet and the remainder of the filling.

Step 3

Bake until the pastries are golden brown, or about 12 to 15 minutes. Serve warm.