Brew some coffee and allow it to cool. You can use instant, or even use cold brew if you have any in the fridge to save time.
To make the tiramisu cream filling, mix the mascarpone cheese with the cream and sift in the sugar until it is smooth and incorporated. You don't need to use an electric whisk, just stir vigorously to avoid lumps of sugar. You want it thick and luxurious.
Slice the mini panettone into six pieces that are all the same width.
Pour the coffee onto a plate and dip one side of each slice of mini panettone into the coffee before placing it in the bottom of a glass. Don't dip both sides as it will become sodden and we don't want that. A quick dip and we're done.
Spoon some of the tiramisu cream filling on top of the panettone and smooth it all over with the back of the spoon to get a flat (ish) layer.
Grate the dark chocolate finely over the top with a cheese grater (use the parmesan setting)
Rinse and repeat! Add another slice of mini panettone, more cream, more chocolate.
Once you have used all your panettone slices, cover the top with the rest of your cream mixture and grate over the rest of your chocolate to cover it completely.
Chill the mini panettone tiramisu in the fridge for an hour for best results to let the flavours infuse and then enjoy!