Mix all ingredients together except for the baking powder in a large bowl. Finally add the baking powder and mix in, leave to rest for half an hour at room temperature. Pour into rectangular silicon baking pan. Bake for 30 minutes at 200 degrees celcius. Cool on rack. Transfer to plate.
*Originally this florentine cake was made using lard instead of olive oil.
** Tip when adding baking powder always use a small sieve to make sure it is perfectly smooth.