Preheat oven to180°C (356°F).
In a mixing bowl, add in all dry ingredients.
Zest a lemon and an orange into the dry ingredients.
Rub the dry ingredient to combine and abrade the zests to work some of the oil out for extra fragrance. Set aside.
In another mixing bowl, add all wet ingredients except the heavy cream. Then beat until creamy.
Add in the dry ingredients into the wet ingredients. With mixer, mix until ingredients are incorporated. Scrape down the bowl a few times while mixing.
Then add heavy cream into the mixture and use a spatula until everything is combined. Set aside.
In another mixing bowl, using mixer, beat the egg whites until bubbly. Add liquid stevia extract. Continue to beat until stiff peak form.
Fold in 1/3 of the egg white meringue into the batter and mix.
Now, add the batter to the remaining meringue. Use "cut and fold" method to combine everything.
Pour the batter into a 6" cake tin.
Bake at 180°C (356°F) for 30mins.