Preheat oven to 350 degrees and line a large baking sheet with parchment paper.

In a skillet, heat olive oil over medium heat. Add mushrooms, stir to coat with oil, spread evenly in the pan, and allow to sit undisturbed for about 4 minutes.

Add wine and butter to the skillet. Allow butter to melt. Then, add garlic and onion.

Cook for 3-4 minutes, strirring every so often, until onions and garlic are fragrant and mushrooms have softenened.

Season with salt and pepper. Stir and remove from heat. Stir in the herbs and set aside.

On a lightly floured surface, unroll the puff pastry. Roll out the dough just to remove the creases.

Spread the mushroom mixture (without pan juices) down the center of the puff pastry sheet. Top with shredded mozzarella.

With kitchen scissors, or a sharp knife, cut the ends of the dough up towards the filled center in 1-inch strips.

Take an end strip and begin overlapping each strip until a braid forms. Tuck in or trim ends.

Use a pastry brush to lightly brush on the egg wash and sprinkle with garlic powder.

Bake in the oven for 30 minutes, or until dough is completely cooked through and golden brown.

Allow to cool before cutting in slices and serving.