Make the Batter: In a bowl, whisk together flour, cocoa powder, sugar, and salt. Add eggs, milk, melted butter, and vanilla. Mix until smooth. Let rest for 15–30 minutes.
Cook the Crepes: Heat a non-stick pan over medium heat. Lightly butter it. Pour about 1/4 cup of batter and swirl to spread thin. Cook 1–2 minutes per side. Repeat.
Fill with Nutella: Spread Nutella on each warm crepe.
Add Strawberries: Place sliced strawberries on top of the Nutella. Fold or roll the crepe.
Serve: Dust with powdered sugar and top with whipped cream if desired. Serve immediately.