Slice and lay the croissants open. Cover each croissant bottom with slices of brie to cover. Spread with 1/2 tablespoon preserves, sprinkle with 1/2 tablespoon chopped glazed pecans and 1/2 teaspoon brown sugar. Cover with top of croissant.
Heat large skillet over medium heat. Spray sandwiches with no-stick cooking spray. Place sandwiches, sprayed side down, in heated skillet. Cover skillet and brown sandwiches 4 to 5 minutes or until golden brown. Spray tops of sandwiches before turning to brown second side.
Remove sandwiches from skillet. Allow to rest covered, about 3 minutes. Cut diagonally, sprinkle with cinnamon sugar, if desired, and serve warm.