Line an 8x8 baking pan with plastic wrap, spray with oil, and generously dust with powdered sugar or cornstarch. Set aside.
Add the sugar/allulose, salt, and 1 cup of the water to a small saucepan and bring to a simmer to create a simple syrup, whisking to dissolve the sugar.
In a separate bowl, dissolve the three sachets of Gelatin Alternative into 1/2 cup water and let sit for a few minutes to thicken. Add to the saucepan with the simple syrup and whisk to combine before removing from the heat.
In your stand mixer, beat the egg whites on high until medium/stiff peaks form. Turn the mixer down to low and slowly pour the sugar mixture into the egg whites to create a marshmallow fluff.
While it is still mixing, add the sachet of Vanilla Protein Pudding and whisk for another 30 seconds on high.
Quickly pour the fluff into your prepared baking pan, smooth the surface, and let it rest for about 4 hours or overnight.
Once set, dust with more powdered sugar or cornstarch, turn out onto a lined surface, and slice into squares.
