Put in a dry grinding mixie. Sprinkle sugar, cocoa, walnuts and essence. Run mixie till fine brown crumbs are formed. Take a slice of bread on a clean surface. Sprinkle some milk all over slice.
Sprinkle cocoa crumbs thickly over it.
Repeat one more layer of slice and crumb over it. Press and roll tightly like a swiss roll. Roll in the biscuit crumbs to cover completely. Repeat for remaining 2 slices and cocoa crumbs. Hold in place by either tying with twine, or toothpicks.