Heat the waffle iron according to the appliance manufacturer’s directions. Allow it to become fully preheated before cooking, as sufficient heat helps create an evenly browned, golden exterior.

In a broad, shallow bowl, thoroughly whisk together the whole milk, eggs, maple syrup, vanilla extract, and salt. Continue mixing until the custard is smooth and the ingredients are evenly incorporated.

Place one brioche slice into the custard and press it gently to ensure both surfaces are evenly coated. Lift the bread from the mixture, allowing the excess custard to drip back into the bowl, then transfer the soaked slice to a rimmed baking sheet.

Repeat the same process with each remaining slice. Leave the coated brioche to rest for approximately 2 minutes so the custard can penetrate the bread more thoroughly.

Lightly coat the preheated waffle iron with cooking spray to reduce sticking. Position one custard-soaked brioche slice on the iron, then carefully lower the lid without pressing it down forcefully.

Cook for approximately 3–5 minutes, or until the French toast develops a golden-brown surface and the waffle iron has largely stopped releasing steam.

Repeat the cooking process with the remaining soaked brioche slices, applying additional cooking spray when necessary.