Debark the sandwich toast and roll it flat with a rolling pin. Spread with the chocolate spread of your choice - amount to your own taste. Roll up the toast slices.
Whisk egg and milk, place a pan with the butter over medium heat. Dip the toast rolls in the egg mixture so that the whole roll is covered with the mixture. Drain the excess mixture and then fry it in the pan until golden brown. After frying, let it drain briefly on paper towels and then toss in cinnamon and sugar.
As a delicious variant, simply mash a banana and add it to the chocolate spread as a filling. Then continue as already described.