Pre-heat oven: 180°C / 160°C (fan) / Gas Mark 4 / 350°F
Melt the butter (microwave for 30-60secs) and stir in the sugars until smooth.
Lightly beat the egg and add this to the slightly cooled butter mix along with the vanilla extract, stirring until fully combined.
Add the ground almonds to the mix and stir until smooth.
Sieve the baking powder into the mixture and then add the chocolate chips to the sieve. Sift the cornflour through this into the mixture to coat the chips.
Set the chocolate chips to one side and fold the sifted flour and powder into the mixture.
Add the whiskey to the mixture and stir until smooth.
Stir in flour-coated chocolate chips until spread evenly throughout.
Pour the cookie mix into a lined 8inch square tin, smoothing it out evenly, before sprinkling the flaked almonds on top and baking for 20-25mins, or until there is only a slight wobble in the centre and it has a crispy top.
Remove the cookie bars from the oven, and sprinkle the sea salt over the top, before allowing them to cool and cutting them into squares.