Heat milk in a large saucepan just until tiny bubbles form; remove from heat. Cube bread and add to milk; stir until smooth.
Add sugar, cocoa and egg yolks; stir until well blended. Add butter and vanilla; set aside. Beat egg whites until stiff peaks form; fold into mixture along with chocolate chunks.
Pour into 6 lightly greased custard cups; set cups in a larger pan filled with one inch of hot water.
Bake at 350 degrees for 40 minutes, or until firm. Garnish with whipped cream and baking cocoa; serve warm or cold.