In a large mixing bowl, combine warm milk, yeast, and sugar. Whisk until well blended and let the mixture rest for about 10 minutes until frothy.

Add the remaining dough ingredients including flour, salt, butter, and yogurt (or egg) to the yeast mixture. Mix until combined and knead for about 7-10 minutes until smooth and elastic.

Place the kneaded dough into an oiled bowl, cover it, and set it in a warm area to rise for 60-90 minutes, or until doubled in size.

In a saucepan over medium-low heat, melt butter, cream, espresso powder, and sugar. Stir until combined, then add dark chocolate pieces, stirring until melted.

Once the dough has risen, punch it down and roll it out into a 12x14" rectangle. Spread the cooled filling across the dough and cut it into 6 strips.

Place the shaped rolls into a buttered baking pan, cover loosely with a cloth, and let them rise for 30-45 minutes.

During the final 20 minutes of the rolls' second rise, preheat your oven to 375°F (190°C).

Pour heavy cream evenly over the rolls before placing them in the oven. Bake for 20-25 minutes or until lightly golden.