Add all the ingredients for the dough except for butter, in a standing mixer bowl. Mix well and then knead for 10 minutes. Add in cubed butter bit by bit until everything is incorporated, this process will take from 5-10 minutes. Then knead for another 10 minutes. You'll get a soft and very sticky dough.
Cover the bowl tightly with cling film and leave until the dough rises to double its size. This could take around 1-2 hours.
Second proof
Grease the countertop and your hands with some oil. Don't use flour as we don't want to add extra flour to the dough. Place the dough on the countertop and stretch it into a rectangle, more or less. Sprinkle chocolate chips on top.
Fold the dough and gently knead it to distribute the chocolate chips evenly. Divide the dough into 6 equal pieces.
Assemble and bake
Form each piece of dough into a ball. Place them into mini panettone molds (2.5x1.75 inch or 6.35x4.4 cm), on a baking tray. This will make it easier to move them around without deflating the dough. Cover the top loosely with cling film. Leave until the top of the dough rises to almost 1 inch (2.5cm) from the brim of the mold. Don't overproof it.
Gently brush the top with some egg wash. Bake in a preheated oven at 350ºF (175ºC), on a lower ⅔ rack for 25 minutes, or until a skewer inserted comes out clean. Cool completely. Enjoy your mini panettone with chocolate chips!
Notes
We highly recommend using a kitchen scale for this recipe as it's more precise.