Combine the milk, yeast and sugar in a small bowl or jug and whisk until well combined.
Using the large bowl of a stand mixer with the dough hook attached, add the flour, cocoa powder, mixed Spice, yeast mixture, melted butter and egg.
Add the chocolate chips and knead for 1 minute. Make sure that the chocolate chips are evenly distributed.
Place the dough on a floured surface and knead lightly.
Using a sharp knife, divide the dough into 15 equal pieces. Roll into balls and place on a baking tray.
Make the chocolate sauce and pipe across the proofed buns. Cook in a preheated oven for 20 minutes until the buns are cooked through.
Allow them to rest in the baking pan for 5 minutes and brush generously with warm raspberry jam - before removing and placing them on a wire rack to cool for a further 20 minutes.
Pan de Leche