Pre-heat the oven to 180 degrees C (350 degrees F).
Cream the butter and sugar in a stand mixer, or by hand, until pale and fluffy. The butter must be at room temperature – just soft enough without being runny before you add in the sugar.
Beat in the vanilla essence.
Remove the bowl from the mixer stand and stir in the flour until you have created a mixture that is crumbly but when you press it in your hand as in the photo it holds together.
Place the dough in a bowl in the fridge for an hour or so to rest.
Remove from fridge and press the dough either into a square pan or a round cake tin that has been lined with parchment paper.
If you are making it in a pan, then mark out where the pieces will be cut with a knife as this will make cutting easier.
Prick the dough with a fork to ensure it cooks evenly – it may get a bit crumbly when you do this, but it’s fine – just smooth the surface again and try one more time.
Place in the oven, bake for 20-30 minutes, and make sure you don’t forget about the shortbread – it must be just golden in color – not brown!
Cut the slices as soon as the shortbread comes out of the oven – otherwise when it cools it will tend to break, when it’s hot you get clean slices.
Serve with tea.