Preheat the oven to fan 160C, 180C, gas mark 6. Line a cup (shallow not muffin tin) cake tin with 6 cake papers.
Use an electric whisk to beat together the butter or margarine, sugar and salt until pale and soft, it may take several minutes to become paler. With the whisk running gradually add the beaten egg, whisking between additions until you have a smooth, stiff mixture. If the mixture splits (appears curdled) add a tsp of Homepride flour to bring it back together. Add the flour and fold in carefully. Spoon into the paper cases and bake for 15-20 minutes until golden and risen – they should spring back when touched gently.
Remove to a wire rack to cool.