My mom typically serves various versions of baked brie around the holidays, so I essentially grew up eating it. It's a classic appetizer with limitless variations. Different jams work well for a salty/sweet appetizer, or you could make it more savory with roasted garlic.
I served this during a long-overdue girls' night in this past week. All three of the ladies I spent the evening with are "food people," so just as I expected when I put this together, nobody turned their nose up at baked cheese with onions and sweet nuts. It's a surprisingly perfect combination, and not surprisingly at all, I didn't come home with any of it. Maybe I ate most of it, maybe I didn't...
You will need:
1 wheel Brie cheese (double cream is the meltiest in my experience), rind intact or cut off
1 sheet puff pastry
1 small yellow onion, very thinly sliced
1/2 cup walnuts
1/4 cup (1/2 a stick) butter
1 cup brown sugar
1 teaspoon kosher salt
To a hot pan, add olive oil and once the oil shimmers, add onions. Season with salt and cook over low heat until the onions are soft and caramelized. Remove onions to a plate, cool.
Melt butter in a medium saucepan. Once the butter is melted and just barely browned, whisk in the brown sugar. Add a pinch of kosher salt and remove from heat, stirring every so often to keep the butter and sugar from separating. While the butter cools, lay walnuts in a single layer on a baking sheet, and toast in a 350 degree oven. Bake for 5-7 minutes, or until you can just smell them - be careful they don't burn (it will happen quickly).
Add hot walnuts to butter/sugar mixture, and, working quickly with a wooden spoon, coat all the walnuts evenly. Still working quickly, spread the coated walnuts back onto your baking sheet. Using a fork, separate the nuts from each other, sprinkle with kosher salt, and allow to cool completely. Note: you may want to line your baking sheet with parchment paper or a nonstick mat. I stuck my whole pan in the freezer to cool them quickly.
Using a sharp knife, carefully cut the top rind off of the wheel of Brie (optional - your toppings will melt into the brie more if you remove the rind, but it is totally edible).
Lay your puff pastry on a baking sheet and place the Brie on top of it, cut side up. Spoon caramelized onions over the top of the cheese, then layer on cooled candied walnuts.
Wrap the cheese in the puff pastry by lifting each corner of the pastry toward the center of the Brie and pressing gently. Cut off any excess dough. If you'd like, you can make something decorative (like leaves) with the excess and place them on top of the dough.
Bake at 350 degrees for 25-30 minutes or until the dough is golden brown. Serve hot with sliced apples, crackers or baguette slices.