Preheat the oven at 180 degrees celsius or gas mark 4
Line a square baking tray with parchment paper and set aside.
In a large bowl, add all of the dry ingredients and combine.
Stir in the melted butter and the egg yolks with the almond milk until everything is mixed together evenly then set aside.
Whisk the egg whites using a hand handle whisk or an electronic version if possible until the egg whites form soft white fluffy peaks.
Carefully fold the egg whites into the batter, rotating the bowl with each fold. If folding in the egg whites appears too difficult, run the batter with the egg whites in a food processor or mixer for a few seconds only to combine and ensure the egg whites retain air in order for the cake to be fluffy.
Pour the cake batter into a square baking tray.
Bake the cake in the oven for 40-50 minutes, it should be golden brown and firm to the touch. Test the readiness by inserting a skewer, if it comes out clean, its cooked in it's entirety or continue to cook if the skewer is left with residue.
Remove the cake from the oven and place on a cooling rack
Store in an air tight container and eat within a few days or freeze for longevity.