Preheat oven to 350 degrees F.
Place the brie round in a brie baker or ovenproof baking dish.
In a skillet, over medium heat, melt the butter and add the chopped walnuts and pecans. Stir occasionally until the nuts start to brown.
Add the cinnamon and stir again to combine. Remove from heat and set aside.
Add 2 tablespoons of the maple syrup to the slightly cooled nuts in the pan.
Pour the nut-and-maple-syrup mixture over the brie. Drizzle another tablespoon of maple syrup over the mixture and bake in a 350-degree oven for 20 minutes.
Serve with toasted crostini or for a GF option, sliced apples.