Dice the apple small: Cut into pieces about 1/4 inch across, no bigger. Large chunks split the fritter open in the oil. A firm tart apple such as Granny Smith works best.
Mix dry: Whisk the coconut flour, sweetener, baking powder, protein powder, xanthan gum, cinnamon, nutmeg and salt together, breaking up any lumps.
Add wet: Whisk the eggs, almond milk and melted butter in a second bowl. Pour into the dry and stir until combined, then fold in the apple.
Rest 2 minutes: Coconut flour absorbs slowly. The batter looks too wet at first and thickens to scoopable within two minutes. Do not add more flour during this time.
Heat the oil: Bring about 1 inch of avocado oil to 350°F in a heavy pan. Use a thermometer. Too hot and the fritters break apart on contact; too cool and they turn greasy.
Form and fry: Shape into 12 balls, packing each tightly between your palms. Fry 3-4 at a time for 1-2 minutes per side until deep golden. Do not turn them early.
Drain: Lift onto paper towels, then move to a wire rack so the undersides do not steam soft.
Glaze: Whisk the powdered sweetener, cream and vanilla until smooth. Let the fritters cool 5 minutes, then drizzle. Glaze applied to piping hot fritters slides straight off.