Measure out the dry ingredients and put into a electric mixer. Add the butter (doesn't matter if salted or unsalted) and blend until in a dough form.
Sprinkle some extra plain flour onto a work surface or tray (put some also on the rolling pin so it doesn't stick) and carefully flatten the dough with your hands and roll out to about an inch in thickness. Use cookie shapes (lovehearts are pretty snazzy) or shape with a sharp knife alternatively. Line a baking tray with greaseproof paper and place the shortbread onto it. Put into the oven at 150-160oC for approximately 30 minutes but check at 20. They should come out crisp and a nice yellowy colour. Leave to cool for about 10 minutes, as they can easily crumble when warm.
When warm, you can sprinkle a pinch of caster sugar on each biscuit.
After doing that, you can dip them into the white or dark chocolate, melted by placing in a glass bowl over bowling water.
I add little sweets to give them that extra specialness, but to be honest, anything would look good on them and sure taste it!
Try doing love hearts, dipping one half in white and dipping the other in dark, transfering back to the tray. They can be left in the fridge for an hour or so for the chocolate icing to solidify.