Clean the mushrooms and remove the stem. Place them bottom side up on a baking dish. Put about 1 tablespoon of brie into each of the mushroom cavities.
In a small bowl, combine the rest of the ingredients and about 2 tablespoons of olive oil and season the mixture with salt and pepper. Fill the mushroom cavity with a small scoop of the bread crumb mixture.
Transfer the baking dish to the oven and bake for about 20-25 minutes until the mushrooms are tender and then cheese is melted.
Remove the baking sheet from the oven and serve.
Notes
These are easy to make ahead of time and bring to an event if you’re in charge of appetizers, and if you’re hosting and want to serve these, you can prep them a day ahead of time and just bake them off when the moment is right!