Mix the flour, Cocoa, dried yeast, 15ml (1 tbsp) caster sugar together in a large mixing bowl and make a well in the centre. Pour half the milk in the centre of the well. Add the melted butter and egg. Gently mix into the flour using a wooden spoon with a little milk to form a smooth paste.

Gradually pour and mix in the remaining milk, carefully stirring in the dry ingredients from the outside of the bowl to form a slightly sticky, moist dough in the centre of the bowl.

Turn the dough on to the work surface and knead until smooth and elastic, and the dough no longer sticks to the work surface and is silky smooth; this will take about 10 minutes. Only use flour to dust the work surface or your hands if the mixture is very sticky - the longer you work the dough the less sticky it will become.

Put the dough in a large lightly oiled bowl, big enough to allow room for the dough to double in size. Cover with a clean tea towel and leave to rise at a coolish, room temperature, out of draughts, for about 2 hours until doubled in size.

Once the dough has risen satisfactorily, push the dough with your knuckles to deflate it and turn it on to a lightly floured work surface. Form the dough into a ball and let it rest for 5 minutes on the work surface.

Line trays with baking paper. Divide the dough into 15 pieces, and form each into a round ball and arrange, well spaced, on the baking trays. Lightly brush vegetable oil onto the cling film and cover each tray of dough balls with the cling film. Leave in a warm place to prove for 20 minutes until doubled in size.

Meanwhile, towards the end of proving, heat the oil for deep frying in a large saucepan to 180°C (350 F). Cook the dough balls in 3 batches, turning them in the oil for 4-5 minutes, until they are puffy and darker in colour, and crisp when tapped. Drain well on kitchen paper and keep warm.

Whilst the dough balls are still warm, insert the pouch of Rich Chocolate Easy Fill into each one through the bottom or side to generously fill.

Grind the Vanilla Grinder approximately 15 grinds into the remaining caster sugar and mix together. Toss the filled doughnuts in the sugar to coat them whilst still warm. Cool on a wire rack for about 30 minutes and then the doughnuts are ready to be served slightly warm, with any remaining vanilla sugar mix for dipping.