Mix water and cocoa powder. Add sugar and vegetable oil. All stir until dissolved sugar crystals. Add soda, pour vinegar. Stir.
Add the sifted flour and grated chocolate. Stir.
Now let's deal with the stuffing. Take the paste, mash it with a fork. Pour water (if desired, you can replace the water with milk). Stir. Pour a couple of tablespoons of flour (without slides). Stir. Get the adhesive mass.
In molds put paper capsule. Pour the dough so much that the filling then did not fall to the bottom of the mold.
With wet hand to take holicow mass, and form into a ball (about a walnut),.. The main thing is that the filling was in the middle and did not touch the edges, if possible..))) otherwise will leak when baking.
On top again put the dough, about a tablespoon, that would be well-covered stuffing. Put in a preheated 180 degree oven. And bake until cooked. I have so quickly rose and baked that I almost missed this moment))) baked minutes 20-25 (electric oven with convection)
And now we take out the cupcakes from the oven, cool down and eat)))
And if desired, you can still sprinkle them with powdered sugar.