Prepare the almond coating: Place the sliced almonds in a shallow dish and gently break up any very large pieces so they can coat the bread evenly.
Make the custard mixture: In a large bowl, whisk together the eggs, whole milk, vanilla extract, cinnamon, brown sugar, and salt until smooth and well combined.
Dip the bread: Dip each slice of bread into the egg mixture, coating both sides evenly. Do not soak the bread for too long, or it may become too soft.
Coat with almonds: Immediately press both sides of each soaked bread slice into the sliced almonds. Gently press the almonds onto the bread so they stick well.
Heat the skillet: Place a large skillet over medium heat and melt the butter. Make sure the skillet is hot but not smoking before adding the French toast.
Cook the first side: Place the almond-coated bread into the skillet and cook for about 3 minutes, or until the bottom is golden brown and crispy.
Flip and finish cooking: Carefully flip each slice and cook for another 2–3 minutes until the second side is golden and the French toast is cooked through.
Serve immediately: Transfer the French toast to serving plates. Dust with powdered sugar, add fresh berries, and drizzle generously with maple syrup.