Prepare the Cranberry Sauce: In a medium-sized saucepan, combine the fresh cranberries, granulated sugar, and water. Over medium heat, cook the mixture, gently stirring occasionally, until the cranberries burst and the sauce thickens (about 10-15 minutes). Once thickened, remove from heat and allow it to cool for a few minutes.
Preheat the Oven: Set your oven to preheat at 375°F (190°C).
Prepare the Phyllo Dough: On a clean, flat surface, lay down one sheet of phyllo pastry. Lightly brush it with olive oil using a pastry brush. Layer two more sheets on top of the first, brushing each with olive oil. Once layered, cut the phyllo stack into squares approximately 4x4 inches.
Form the Tartlet Cups: Gently press each phyllo square into the cups of a muffin tin, creating a shell shape. Make sure to press them carefully to maintain their layers and repeat with the remaining phyllo squares until all are formed.
Fill the Tartlets: Into each phyllo cup, place a small piece of Brie cheese. Then, add a generous spoonful of the cooled cranberry sauce atop the cheese, followed by a sprinkle of chopped fresh rosemary and a dash of black pepper.
Make the Egg Wash: In a small bowl, beat the egg with a splash of water until well combined. Using a pastry brush, lightly brush the edges of each phyllo cup with the egg wash to achieve a beautiful golden color during baking.
Bake the Tartlets: Carefully place the muffin tin into your preheated oven. Bake for 15-20 minutes, or until the phyllo is golden brown and crispy.
Cool and Serve: After baking, remove the tartlets from the oven and allow them to cool in the tin for a few minutes. Then, gently transfer them to a serving platter.
Notes
Serve warm on a decorative platter and garnish with extra rosemary and olive oil.