Preheat oven to 350 degrees F (175 degrees C). Grease an 8x8 inch baking dish.
In a small bowl, mix the sugar, cocoa powder, cinnamon, and salt. In a medium bowl, whisk together the eggs, milk, vanilla, and vegetable oil. Add the sugar mixture to wet ingredients and stir until combined.
Cover the bottom of the prepared baking dish with an even layer of the crumbled biscuits. Pour the liquid mixture evenly over the biscuits. Press down onto the biscuits with the back of a large spoon to moisten them.
Place the 8x8 inch baking dish into a larger high sided baking dish. Place dish on oven rack. Pour boiling water halfway up the sides of the 8x8 inch dish. Bake in preheated oven for 45 minutes, or until pudding is set.