To make the chocolate cream
1. Finely chop chocolate and place in a stainless-steel bowl.
2. Place sugar and water in a small heavy-based saucepan over medium heat and turn into caramel. While the sugar is cooking warm cream A
3. When the caramel turns a medium golden brown, slowly and carefully add cream A a little at a time until fully incorporated. Stir together to make sure all of the sugar has dissolved in the cream.
4. Remove from heat and pour the caramel cream mixture onto the chocolate and stir until chocolate has dissolved. Once the chocolate has fully dissolved mix in cream B. Refrigerate the mixture overnight to chill completely.
To make the maritozzo dough
1. Place the flour, sugars, salt and yeast in the boil of a stand mixer fitted with the dough hook and mix for 1 minute to distribute the yeast evenly. Add the milk and eggs and mix on low speed for 15 minutes to start developing the gluten.
2. Add the cold butter a few pieces at a time. Stop to scrape down the sides and bottom of the bowl and push the dough off the hook if needed to make sure all the butter is incorporated. This mixing process will take about 8-10 minutes.
3. Check the gluten is developed enough by performing a windowpane test. To do this, take a small ball of dough and gently stretch it with your fingers. You should be able to stretch it thin without the dough breaking. If the dough breaks easily, continue mixing for a few minutes more to further develop the gluten, then test again.
4. Transfer dough into a bowl and cover. Leave to rest a room temperature for 30 minutes. Now stretch and fold the dough by lifting one side up and over the other. Do this five or six times. Cover and set aside at room temperature for a further 30 minutes.
5. Perform another set of stretch and folds to the dough. These help to develop strength in the dough while also starting the fermentation process. Place the dough in a clean, lightly oiled bowl, cover and refrigerate overnight to further ferment.
6. Turn the dough out onto a lightly floured bench and cut it into 24 pieces, or 45g each to be extra precise. With each piece, gently flatten the dough and bring the edges together in the middle to form a rough ball, then turn it over so the seam is at the bottom. Cup your hand over the dough and use firm pressure to roll it on the bench until it forms a nice tight round ball with a smooth, even surface. Cover the dough ball again with the damp tea towel, and leave them to rest at room temperature for 20 - 30 minutes.
7. Take each maritozzo ball and knock it flat, then fold the edges into the middle and turn it over so the seam is at the bottom. Using firm pressure, roll it into your hand on the bench again.
8. Place the maritozzo balls on a tray, every spaced to allow room for rising. Lightly cover with plastic wrap and leave to rise for 2-3 hours, or until risen by half.
9. Preheat the oven to 165c 20 minutes before baking. Make the egg wash by lightly whisking all ingredients together. Once proofed egg wash each maritozzo then bake for 8-10 minutes. Turn the tray after 8 minutes to ensure an even bake.
10. Once the buns have cooled completely whip the prepared chocolate cream until soft and light. With a serrated knife cut open each maritozzo filling with the freshly whipped cream. With a microplane or grater generously shave chocolate over the top to finish.