Dissolve yeast in warm water with 1 tablespoon sweetener. Let sit 5 minutes until foamy.
Combine Ketonia Bread Mix, remaining sweetener, eggs, and melted butter. Add yeast mixture and mix to form dough.
Cover and let rise in a warm place for 1 hour.
Roll out dough and cut into circles. Place on parchment-lined sheet.
Let donuts rise another 30 minutes.
Heat oil to 350°F. Fry donuts 2-3 minutes per side until golden. Drain on paper towels.
For filling, whip heavy cream with sweetener, vanilla, and pudding mix to stiff peaks.
Fill a piping bag with cream. Poke a hole in each donut and pipe in filling.
Dust with powdered sweetener if desired.