Bring 1/4 cup water to a rolling boil in a small sauce pan over medium high heat. Add butter, 1 piece at a time, whisking to combine well. Remove from heat: Stir in chocolate until completely melted. Set aside.
Whisk together flour, sugar, and salt in a medium bowl. Whisk together milk, eggs, and vanilla in another medium bowl. Gradually add milk mixture to flour mixture, whisking until smooth.
Add chocolate-butter mixture, whisking until well smooth.
Refrigerate for at least 2 hours This will slightly thicken mixture.
Lightly coat 8 inch crepe pan with melted butter. Heat until it starts to smoke. Remove pan from heat? our about 2 tablespoons batter into pan, swirling to cover bottom. Reduce heat, Cook, flipping once, until edges are golden and center is dry. about 30 seconds per side. Slide crepes onto plate. Repeat process with remaining batter. This will make approx 30 crepes. The time is an estimate.