Preheat your oven to 350 degrees Fahrenheit. Arrange the mini phyllo shells on a parchment-lined baking sheet so they are spaced evenly, ensuring they do not touch each other during the baking process.
Cut the Brie cheese into small cubes, roughly half an inch in size, so they fit comfortably inside the pastry shells. It is not necessary to remove the white rind, as it is completely edible and helps the cheese hold its shape slightly as it melts.
Place one cube of Brie into each phyllo shell. Top the cheese with a generous teaspoon of cranberry sauce. If you are using walnuts, sprinkle a few pieces over the cranberry sauce now so they can toast slightly in the oven.
Slide the baking sheet into the oven and bake for 10 to 12 minutes. You want the cheese to be bubbly and melted, and the phyllo shells to be a light golden brown and extra crispy.
Remove the tartlets from the oven and let them cool for just a minute or two. Drizzle the honey over the tops while they are still warm and garnish each one with a tiny sprig of fresh rosemary for a pop of green and a fragrant holiday aroma.
