Wipe shaggy manes with a damp paper towel to clean, then slice in half and dice along with onion and ham.
Sauté mushrooms, onion, and ham in 1 tablespoon butter until the mushrooms are golden and the onion is caramelized. Add minced garlic during the last minute, then set aside to cool.
In a medium bowl, sift flour, sugar, Tony Chachere's, baking powder, and baking soda. In a smaller bowl, whisk egg, buttermilk, and the remaining melted butter.
Gently mix wet ingredients into dry ingredients, then fold in shredded cheese and cooled mushroom mixture.
Heat waffle iron and spray it with non-stick cooking spray. When the waffle iron is ready, add approximately ⅓ cup of batter for each 4"x4" waffle.
Seal the waffle maker and cook waffles for 2 to 2-½ minutes or until they stop steaming and become crispy.
Notes
To keep the waffles from getting soggy while you're making the rest, stand them up on a rack. This allows the steam to dissipate instead of collecting under the waffle.
If you have access to more shaggy mane mushrooms, you can add more inside the batter and sauté the rest to serve over the waffles.
The batter can be made ahead of time, but it has a tendency to thicken over time. This problem can be solved by adding a small amount of milk to the batter.
Leftover waffles can be stored in the refrigerator or frozen.
To reheat cooked waffles, simply pop them in a toaster. Another option is to bake them in a 350°F oven until crisp.