Directions
Pre-heat the oven to 175C. Line a standard rectangular slice pan with baking paper. Tip: A great tip to get your baking paper to stay down is to scrunch it into a ball, before flattening it out into the pan. I also like to add generous overhang of baking paper on either side of the pan as it makes it much easier to lift out your slice.
Soften the butter by cutting it into cubes and microwaving on a very low heat for about 90 seconds. You can also pop the diced butter in the sun for a while.
Combine flour, sugar, vanilla, salt and butter in a large bowl.
Use your hands to massage the butter into the dry ingredients until a nice dough forms, you could also use a food processor for this step.
Press dough into lined pan and place in pre-heated oven for 18-22 minutes, checking often. You want it to be just golden brown.
While your base is doing its thing in the oven, prepare your lemon topping. Combine all topping ingredients and mix thoroughly with a whisk until everything is well combined.
Pour topping mixture over browned shortbread base, return to the oven for a further 20 minutes. The topping will still be a little wobbly, but it will firm up as it cools.
Remove slice from oven, allow to cool for 15 minutes, then lift out of pan and allow to cool completely before cutting into small bars.