These pillowy balls of dough are filled with homemade raspberry jam. One of the trickiest things about making doughnuts is the frying time – the sugar in the enriched dough means that they brown very quickly, in turn making it tempting to remove them from the oil before they are cooked in the middle. With that in mind, make sure you fry the doughnuts for at least 2 minutes on each side.
Make the dough. Pour the milk into a jug. Add the egg and beat everything together. Tip the flour into a mixing bowl and add the butter. Add the yeast to one side of the bowl and the salt to the other, then add the sugar and stir to combine.
Slowly add the milk mixture to the flour mixture, stirring with your hands until you form a dough. Knead the dough in the bowl for 4 minutes.
Tip out the dough onto a lightly floured work surface and knead it well for 10 minutes, until the dough is smooth and elastic.
Place the dough into a clean, oiled bowl, cover it and leave it at room temperature to rise for about 1 hour until doubled in size.
Meanwhile, make the jam. Tip the raspberries into a small, deep-sided saucepan. Add the sugar and bring the mixture to the boil over a low heat. Crush the raspberries and sugar together using a potato masher, then when the sugar has melted, increase the heat and boil for a further 4 minutes. Remove the pan from the heat and carefully pour the jam into a shallow container. Leave to cool and set.
Tip out the risen dough onto a very lightly floured surface, and knock it back by kneading it a few times. Divide the dough into 6 equal portions and shape each portion into a ball.
Place the balls on a floured baking tray, spacing them evenly, and leave them to rise, for about 1 hour, until almost doubled in size.
Heat a deep fat fryer to 180°C/350°F (if you don’t have a deep fat fryer, two-thirds fill a deep saucepan with vegetable oil and heat it until it reads 180°C/350°F on a cooking thermometer, or until a cube of day-old bread sizzles, floats and turns golden within 30 seconds). In batches of two doughnuts at a time, carefully lower each doughnut into the fryer, frying each side for about 2 minutes, until golden brown all over.
Remove the cooked doughnuts from the oil and set them aside to drain and cool on kitchen paper, repeating until you have fried all the doughnuts.
While the last batch is cooling, sift the icing sugar into a bowl. Add 2 tablespoons of water and the raspberry extract, if using, and mix to a thick coating consistency. Mix in enough food colouring to make a bright pink icing.
Spoon the cooled jam into the piping bag fitted with the jam nozzle and plunge the nozzle into the side of each doughnut. Fill the centre of each doughnut with equal amounts of the jam.
Dip the top of each doughnut into the pink icing to coat it in a neat circle. Shake off any excess, then leave the doughnuts on a wire rack until the icing has set a little. Sprinkle the doughnuts with sugar strands, then leave the decoration to set fully before serving.