Ok, so I dealt with those lemons I had sitting around and I ended up with yummy lemon slice. Win!
For the base:
¾ cup icing sugar
1 ½ cups flour
For the topping:
55g melted butter
200g caster sugar
Preheat the oven to 180˚C and lightly grease or line a 20 x 20cm tin with baking paper. Finely grate the zest of two lemons and juice all three.
Combine the base ingredients in a food processor, or rub the butter into the dry ingredients and work into a smooth paste with your fingers. Press the dough evenly into the prepared tin and bake in the oven for 15-20 minutes, or until it is just beginning to go golden (Do not over cook as it will be going back into the oven later on).
Mix the topping ingredients in a bowl until well combined. If you make the topping mixture in advance make sure you give it another stir before you pour it as the sugar settles at the bottom of the bowl.
Pour the mixture onto the hot biscuit base and return to the oven for another 30 minutes. Rotate the tray after 15 minutes.
Remove the tray from the oven and set on a wire rack to cool in the tin.
Once cool, dust the top with icing sugar or drizzle with melted chocolate. Cut into squares or wedges. Store in an airtight container, preferably in the fridge.