My mother’s favourite dessert is a really tart citrus tart.  Like, it has to really bite as you take a mouthful, and then once in your mouth it takes on this sweeter, smooth consistency. Ingredients Base: 1.5 cups plain flour 1/4 cup self raising flour pinch of salt 1/2 cup caster sugar 100g butter 1 egg Filling: 1/2 cup lemon…