Preheat your oven to 375°F (190°C). Arrange the baguette slices on a baking sheet in a single layer.
Brush each slice lightly with olive oil and sprinkle with salt. Bake in the preheated oven for 8-10 minutes until golden and crisp.
While the crostini are baking, prepare the cranberry sauce. In a saucepan over medium heat, combine the cranberries, sugar, water, and a pinch of salt. Cook, stirring occasionally, until the cranberries burst and the mixture thickens (about 10 minutes).
Stir in the chopped rosemary and honey, then remove from heat and let cool slightly.
Once the crostini are ready, remove them from the oven and place a slice of Brie cheese atop each crispy round.
Top the Brie with a spoonful of the cranberry mixture, and if desired, sprinkle some chopped walnuts on top for added texture and flavor.
Return the topped crostini to the oven for an additional 5 minutes, until the cheese is warm and slightly melted.
Serve immediately, garnished with a sprig of rosemary or a drizzle of honey if you like.
Notes
Optional to add chopped walnuts for extra texture.