Prepare the cinnamon butter mixture by combining the butter, brown sugar, and cinnamon powder.
Prepare the wet mixture by whisking together the egg, milk, and vanilla extract.
Prepare the cinnamon sugar mixture by combining the sugar and cinnamon.
Assemble the rolls by spreading the cinnamon butter mixture on the bread, then rolling it up.
Dip the rolls in the wet mixture, then coat them in the cinnamon sugar mixture.
Optionally, you can add Nutella or sugar icing to the rolls.
