Preheat the Blackstone griddle to medium-high heat.
Combine maple syrup and cranberries in a cast iron pan or heatproof bowl. Place on the griddle, stirring occasionally as it heats. Let the cranberries pop. Remove from heat if it starts to burn or boil over.
Reduce the griddle heat to medium-low (about 400°F).
In a bowl, whisk together eggs, eggnog, and a sprinkle of cinnamon.
Slice the Brioche bread into 4 thick pieces (approximately 3/4 to 1 inch each).
Dip each slice into the egg mixture, ensuring both sides are evenly coated.
Melt butter on the griddle, spreading it evenly. Place the soaked bread slices on the griddle. Cook until both sides are golden brown, flipping once. You can press the edges of the bread against the griddle briefly to ensure the egg is fully cooked.
Top the cooked French toast with the cranberry maple syrup and sprinkle with powdered sugar. Enjoy!
