In a small bowl, whisk together the sugar and cinnamon. Set the bowl right next to the stove so it's easy to reach when you start cooking.
¼ cup sugar, ½ teaspoon cinnamon
For the French Toast
If your brioche is fresh, slice it ¾ to 1 inch thick and let the slices sit out for a few hours, or dry them in a 200°F oven for 10 minutes.
8 slices of brioche
In a large measuring cup, whisk together the eggs, milk, maple syrup, vanilla, cinnamon and salt until smooth.
4 large eggs, 1 cup whole milk, 1 tablespoon maple syrup, 1 teaspoon vanilla extract, ½ teaspoon cinnamon, pinch of salt
Pour the custard into a shallow bowl or pie plate.
Heat a large skillet or griddle over medium heat and add 1 tablespoon of butter. Let it melt and foam.
1 to 2 tablespoons butter
Dip each slice of brioche into the custard for 10 to 15 seconds per side.
Add the brioche slices to the pan, leaving a little space between each one. Cook for 3 to 4 minutes, until the bottoms are deeply golden brown.
Flip each slice and immediately sprinkle a generous pinch of cinnamon sugar across the top. Cook for another 3 to 4 minutes, until the second side is golden and the centers feel springy when you press them gently.
Transfer to plates and serve right away with pure maple syrup and fresh berries. Add more butter to the pan as needed between batches.