Thaw your puff pastry sheet overnight in the fridge.
Preheat your oven to 190 degrees.
Cut your puff pastry into 24 pieces. You don't want the pieces of brie to be too big or they'll spill out everywhere. So just cut 24 pieces out of about ½-⅔ of the brie round.
In a HEAVILY sprayed and lined mini muffin tin, press each little puff pastry square into the 24 holes. Poke a fork in the bottom of each puff pastry a few times to allow holes for baking.
Next, top each puff pastry with a brie cube, then about 1 tsp fig jam, and a sprinkle of chopped nuts.
You can put the muffin tin on a baking sheet in case anything spills over.
Bake in the oven for about 17-20 minutes until everything is melted and the puff pastry is slightly golden.
Remove from oven, sprinkle with flakey sea salt and garnish each cup with a sprig of rosemary.
Remove the cups from the pan using a fork. Enjoy warm or at room temperature!