Preheat oven to 350 degrees F (175 degrees C). NOTE: If using allulose, bake at 325 degrees F.
Sift protein powder, poppy seeds, sweetener and Further Food gelatin together and set aside.
In a large clean bowl, whip egg whites with a pinch of salt until foamy (save the yolks for "healthified" creme brule, "healthified" coconut custard, OR "healthified" ice cream).
Add cream of tartar and continue to beat until very stiff (you will be able to put bowl upside down and the whites won't fall out).
Add your favorite extract flavor.
Gently fold in the protein powder mixture.
Pour into a greased 10 inch tube pan. Bake at 350 degrees F (175 degrees C) for 45 minutes.
Allow to cool while you make the lemon curd.
Combine allulose, lemon juice, 4 eggs and lemon zest in heavy medium saucepan and whisk to blend; add coconut oil. Whisk constantly over medium heat until mixture thickens and coats back of spoon thickly (do not boil), about 5 minutes.
Pour mixture through strainer into medium bowl. Place bowl in larger bowl filled with ice water and whisk occasionally until lemon curd is cooled completely, about 15 minutes.
Can be made 1 day ahead.
To serve, place one slice of protein sparing angel food cake onto a plate and top with a few tablespoons of lemon curd.