Prepare coals on a grill and let heat reduce to a moderate heat.
In a blender, combine eggs, cream, vanilla, cinnamon, and nutmeg. Blend until the ingredients are smooth. Set aside.
Slice peaches in half and remove the pit. Brush the flesh side of each half with melted butter. Place the peaches on the grill for 5 minutes, or until the flesh side is evenly caramelized and begins to soften. Remove the peaches from the grill and dice them. Transfer to a bowl and add lemon juice and sugar, to taste. Set the peach mixture aside.
Pour the egg batter into a pie plate. Dip the croissant halves into the batter, making sure that each side is coated. Place the croissants on the grill, flat side down. Grill for 1 to 2 minutes, or until the batter appears cooked and the croissant begins to darken; watch carefully, as they will cook quickly. Flip the croissants and grill on the other side for 1 to 2 minutes. Remove the croissants from the grill.
Place the bottom half of 1 croissant on a plate. Add 1/4 of the peach mixture and place the top half of the croissant over the peaches. Pour Bourbon Pecan Maple Syrup over the top and garnish with fresh mint. Repeat with remaining croissants.
Melt butter in a medium saucepan over medium heat. Once the butter begins to brown, remove the pan from heat and add bourbon. Flambe the mixture until the alcohol has burned off and then add the syrup and pecans. Return the pan to the heat and simmer for 10 minutes.