Heat a waffle iron according to the manufacturer's directions.
Whisk together the flours, baking powder, baking soda, salt and sugar in a medium bowl.
Whisk the eggs and butter together in another bowl, and then whisk in the buttermilk.
Add the wet ingredients to the dry and whisk to combine. Rest the batter for 5 minutes.
Lightly coat the waffle iron with nonstick spray. Ladle the recommended amount of waffle batter onto the iron according to the manufacturer's recommendations. Close the iron top and cook until the waffle is golden on both sides and is easily removed from the iron.
Coat the crock of 1 1/2-quart slow cooker with the butter, layer the waffles into the slow cooker, sprinkling with a few tablespoons of the candied pecans in between layers, and set aside.
Whisk together the eggs and sugar in a large mixing bowl. Add the milk, heavy cream, vanilla extract, cinnamon, nutmeg, and salt and whisk until smooth. Pour over the custard over the waffles, then cover with a layer of plastic wrap. Place a large can (or cast-iron skillet) on top of the waffles. The goal is to press the waffles together and help them absorb the custard mixture. Press for 30 minutes.
Set the slow cooker to low and add the crock. Remove the weight and plastic wrap. Cover with the slow cooker's lid and cook on low for 2 1/2 to 3 hours. The custard should be set, reaching a temperature of at least 205 degrees.
Heat your broiler to high. Remove the slow cooker‚Äôs crock from the cooker and remove the lid. Sprinkle the bread pudding with the maple sugar and broil until just brown ‚Äì about 2 minutes.
Cool the pudding for 15 minutes before serving.