Line an 8x8-inch pan with parchment paper and dust with a thin layer of coconut flour.
In a small pot, sprinkle gelatin over 1/4 cup cold water. Let it sit for 2 minutes until firm (blooming).
In a large bowl, beat egg whites with an electric mixer. Gradually add cream of tartar, powdered erythritol, vanilla seeds, and salt. Beat until soft peaks form (1–2 minutes).
Add 3/4 cup boiling water to the bloomed gelatin. Stir until fully dissolved. Stir in liquid stevia.
With mixer on medium speed, slowly pour the hot gelatin mixture into the egg whites. Increase speed to high and beat 3–5 minutes until thick, glossy, and creamy.
Spoon into the pan, spread evenly, and sprinkle with coconut flour. Refrigerate for 2–3 hours until set.
Cut into 36 cubes. Optionally, dip in melted chocolate and roll in desiccated coconut.