In a large mixing bowl, whisk together the eggs, granulated sugar, whole milk, ground cinnamon, and kosher salt until well combined.
Slice the brioche bread into 10 even pieces, each about 1 inch thick. Dip each slice into the custard mixture, soaking for a few seconds on each side.
On a large plate, combine the all-purpose flour and the lightly crushed Fruit Loops. Mix to create a colorful coating.
Dredge each soaked brioche slice in the Fruit Loops mixture, pressing gently to ensure the cereal sticks.
Heat a skillet over medium heat and lightly grease it. Cook the coated slices for about 3-4 minutes on each side until golden brown.
Transfer the cooked French toast to a plate and serve warm with maple syrup and powdered sugar.