In a large bowl, whisk the eggs, milk, sugar, vanilla, and unsweetened cocoa powder.

In a large nonstick skillet, melt the butter over medium heat. Work in small batches, dipping a few pieces of the bread into the egg mixture, flipping once to coat evenly. Place in the preheated skillet. Let cook until golden brown and flip to cook the other side. About 3-4 minutes each side. Repeat until you have cooked all of the French Toast. Keep warm in a 300 degree F oven until ready to plate, if needed. (Tip: the cocoa powder will settle to the bottom of the bowl, so you'll want to continue to whisk the mixture as you work.)

Place one piece of French toast on a plate. Spread with a thin layer of hazelnut spread. Top with another piece of French Toast. Spread another thin layer of hazelnut spread on your top piece of toast. Dust with powdered sugar and garnish with fresh raspberries or slices of strawberries. Serve immediately.