Chocolate Hazelnut Crepe Cake

Name: Chocolate Hazelnut Crepe Cake
Ingredients: 1 1/2 cups whole milk; 1/2 cup water; 3 large eggs; 3 tbsp unsalted butter, (melted (plus extra for greasing the skillet)); 1 tsp vanilla extract; 1 cup all-purpose flour, (fluffed, spooned and leveled); 6 tbsp unsweetened Dutch processed cocoa powder, (sifted); 1/4 tsp coarse Kosher salt ((if using table salt, use half the amount)); 1 1/4 cups cold heavy whipping cream; 1 1/2 tsp vanilla extract; 1/2 cup chocolate hazelnut spread; 1/2 cup chopped hazelnuts, (optional)