Preheat your oven to 350°F (175°C) and line a baking sheet with parchment paper.

Using a serrated knife, carefully cut a circular hole in the top of each brioche bun and scoop out the center to create a hollow cavity, leaving the bottom and sides intact.

Line the inside of each hollowed bun with a slice of prosciutto, pressing it gently against the bottom and sides.

Fill the prosciutto-lined cavity generously with the cubes of Brie cheese.

In a small bowl, whisk together the melted butter, maple syrup, fresh thyme, and black pepper.

Brush the tops and outsides of the brioche buns generously with the maple butter mixture.

Place the stuffed buns on the prepared baking sheet, spacing them slightly apart.

Bake for 12-15 minutes, or until the brioche is toasted golden brown and the cheese is fully melted and bubbly.

Remove from the oven and serve warm immediately.