In small cup, sprinkle gelatin over 2 Tablespoons cold water; let stand a minute or so to soften. Add 3 Tablespoons boiling water; stir until gelatin is completely dissoved and mixture is clear. Cool slightly.
Cook raspberries, erythritol, and stevia over medium low heat until sweetners are dissolved. Cool, then remove seeds by pressing mixture through a fine metal strainer basket with a spoon. Stir in gelatin and set aside.
Whip cream with vanilla extract until soft peaks form. Gently fold in raspberry mixture. Spoon into 6 dessert cups. Serve with chocolate sauce over top, if desired.