1. Preheat oven to 350 degrees
2. Cook fruit on stove in saucepan over medium stirring occasionally until it resembles jelly (15 minutes). Try to work out any large lumps so it won't plug up bag when you try to fill the doughnuts. Let cool.
3. Beat egg whites in mixer until stiff. Fold in protein powder, almond meal, and nutmeg with spoon gently so egg whites are not deflated.
4. Generously spray nonstick mini doughnut tin with cooking spray. Spoon batter into doughnut tin until just fills the rings. Bake for 10-15 minutes at 350 degrees until golden brown on top. Remove from tin and transfer to wire rack to cool.
5. Spoon fruit filling into a ziplock bag and snip off corner (or use piping bag if you have one). Once doughnuts cooled, squeeze in about 2 teaspoons of the filling. For frosting, stir all ingredients until smooth; add more or less water until desired consistency reached. Frost doughnuts if desired.