Preheat your oven to 350°F (175°C) and line a baking sheet with parchment paper.
Place the sourdough loaf on the baking sheet. Using a serrated knife, cut the loaf in a crosshatch pattern to create 1-inch slices, being careful not to cut all the way through the base.
Stuff each cut section of the bread with Brie cubes and spoon small amounts of cranberry sauce into the pockets for even distribution.
In a small bowl, mix together the melted butter, garlic powder, and thyme leaves until combined. Slowly drizzle the mixture over the entire loaf, focusing on the crevices.
Cover the bread loosely with aluminum foil and bake for 15-20 minutes. Remove the foil and bake for an additional 5-10 minutes until the top is golden and crispy.
Let the bread cool slightly, then garnish with fresh rosemary or thyme leaves for an extra aromatic touch. Serve warm and enjoy pulling apart the gooey, flavorful bread!