You can either make the dough for the doughnuts in a breadmaker if you have one, or by hand. First mix the soya milk and cider vinegar together.
If using a breadmaker place the ingredients into the pan in the order recommended by the manufacturer and set to the standard dough recipe.
If making the dough by hand put the flour, protein powder and sugar in a bowl and mix together. Put the salt on one side of the bowl and the yeast on the other.
Make a well in the middle of the flour and pour in the milk and melted butter. Mix together until you have a smooth dough. Knead for 5 minutes. You can also do this in a food mixer with a dough attachment.
Put the dough in a bowl, cover and leave in a warm place until doubled in size.
Once it has risen knock it back, and roll out to about 1cm thick. Cut heart shapes out with a cookie cutter, place on trays and leave to rise again for 30 minutes.
Heat oil in a pan or deep fat fryer to 180C.
Fry the doughnuts, turning once, until dark golden on both sides. Drain on a plate covered with kitchen roll.
Once cooled make red frosting with icing sugar, a little hot water and red food colouring. Then dip the tops of half of the doughnuts in the frosting to coat.
Make the brown frosting with icing sugar, hot water and 1tsp cocoa powder. Dip the tops of the remaining doughnuts in to coat.
Put the left over coloured icings into 2 separate piping bags and pipe the alternate colour icing on the doughnuts to decorate.