Combine the milk and yeast and stand for 15 minutes, until bubbles dot the surface.
Combine the egg replacer with 1 tbs water. Stand for 10 minutes.
Combine the milk, yeast, egg replacer, spices, flour, cacao powder and Natvia in a bowl with a knife. Add the chocolate chips. Knead for about 5 minutes and then place in a bowl, cover with a wet tea towel and leave somewhere warm for about 1 hour, until doubled in size.
Divide the dough into 6 pieces and roll into buns. Place on a greased baking tray and bake in the oven for 30 minutes.
Remove from the oven and stand to cool slightly. Place the melted chocolate in a piping bag, or a zip lock bag and snip a corner. Draw crosses on the top of the buns. Enjoy warm!