Instructions

Step 1
Preheat the oven to 400 degrees F (200 degrees C). Set an oven rack in the center of the oven.

Step 2
Place chicken breasts between 2 sheets of heavy plastic on a solid, level surface. Firmly pound with the smooth side of a meat mallet to 1/2-inch thickness.

Step 3
Melt butter in a saucepan over medium heat. Add mushrooms and cook until softened, about 4 minutes. Add garlic and thyme and cook until mushrooms are tender and most of the liquid has evaporated, 4 to 5 minutes. Reduce heat to medium-low. Stir in cream cheese and season with salt. Cook and stir until cream cheese has completely melted. Remove from heat.

Step 4
Spoon mushroom-cream mixture onto the chicken breasts. Wrap chicken around the mixture and secure with toothpicks. Set chicken bundles, seam-side up, in a baking dish.

Step 5
Bake in the preheated oven for 20 minutes. Remove from oven and brush with Dijon mustard. Sprinkle with Parmesan cheese and return to the oven.

Step 6
Continue baking until no longer pink in the center and the juices run clear, 15 to 20 minutes more. An instant-read thermometer inserted into the center should read at least 165 degrees F (74 degrees C). Discard toothpicks before serving.