Prepare a 7 inch round cake pan with butter (or cooking spray) and cut a round of parchment paper to fit the bottom.
Preheat the oven to 400°F/200°C
Beat the eggs, sugar, salt and vanilla together until frothy.
Add the almond flour and lemon zest, combine to make a thick batter.
Transfer the batter to the cake pan and bake for about 10 minutes.
The cake is finished when the top is golden brown, the sides have pulled away from the pan and a toothpick inserted into the center is clean.
If you'd rather bake at 350°F, increase the cooking time. Begin checking at 10 minutes and look for the signs above to indicate when the cake is finished.
Remove from oven and allow to cool slightly before removing from the pan.
Transfer to a platter and place the cross template on top.
Dust with confectioner's sugar to suit. Remove the template and slice.