Slice the Brioche: Slice each thick slice of brioche into 2 or 3 finger-sized sticks (about 1 inch wide and 4 inches long).
Whisk the Pumpkin Custard: In a shallow pie dish or wide bowl, whisk together beaten eggs, pumpkin purée, milk, maple syrup, pumpkin pie spice, and vanilla extract until smooth and uniform.
Prep Cinnamon Sugar: On a large plate or shallow tray, mix granulated sugar and ground cinnamon until blended.
Dip & Coat: Melt 1 to 2 tablespoons butter in a large non-stick skillet or cast-iron griddle over medium heat. Dip each brioche stick into the pumpkin custard for 3 to 4 seconds per side so it absorbs the custard without becoming soggy.
Pan-Fry Golden: Place sticks into the sizzling butter. Cook for 2 to 3 minutes per side, turning with tongs so all four sides become golden-brown and slightly crisp.
Roll in Cinnamon Sugar & Serve: Immediately transfer hot french toast sticks directly into the cinnamon sugar mixture and turn to coat on all sides. Serve hot with warm maple syrup for dipping.