These cranberry brie bites are an easy, fun, and gorgeous cocktail party appetizer, and your guests will love them! Brie and cranberries are natural companions, and these cute little bites are a seriously tasty combination of sweet, tart, and salty. If you prepare the jam and crostini in advance (which takes less than 30 minutes), these two-bite appetizer toasts take just 10 minutes to assemble.
Combine the cranberries, brown sugar, orange juice, orange zest, vanilla, and rosemary in a small pot. Bring the liquid to a simmer and stir frequently with a wood spoon until the sugar has dissolved. Reduce the heat to medium low and simmer, stirring occasionally, until the cranberries are falling apart and a jam-like consistency has formed, 20-25 minutes. Remove from heat and fish out the orange peels and rosemary stems. Taste for sweetness, and add more brown sugar (start with a tablespoon) if the jam is too tart. Set aside to cool.
Heat the oven to 375°F. Slice the baguette into 24 1/2" slices. Brush each side with olive oil, then lay onto a baking sheet. Sprinkle the slices with salt. Transfer the slices to the oven and bake, flipping once halfway through, until golden brown and crisp, 12-15 minutes.
To prepare the brie bites, top each slice of toasted baguette with a slice of brie cheese and a tablespoon of cranberry jam. Garnish with a small piece of rosemary if desired. Serve at room temperature. The jam will keep in the fridge for 3-5 days in a sealed container.