Heat up the cream, dissolve the yeast in it. Mix the flour, sugar and salt in a bowl. Add the cream and eggs, mix, use a food processor with dough hook to knead the mixture into a soft, smooth dough. Add the butter and continue to knead for approx. 5 mins. Cover and leave to rise at room temperature for approx. 2½ hrs. until doubled in size.
Melt the chocolate and butter in a pan on a low heat.
Sprinkle a little flour on the work surface and roll out the dough to a rectangle of approx. 40 x 50 cm. Spread the filling over the top, leaving a border of approx. 1 cm. Roll the dough up from the long edge, without exerting pressure, cut it into approx. 12 pieces using a bread knife. Place the pieces of dough in the prepared holes. Cover and leave to rise for a further 15 mins. Glaze the brioches with egg.
for approx. 20 mins. in the centre of an oven preheated to 180°C. Remove from the oven, allow to cool slightly and serve warm.