Preheat the oven up to 350F. In a bowl, combine the protein powder, strawberry gelatin, lemon zest, baking powder, and salt. In another bowl, stir together the milk, butter, and eggs. Gradually incorporate the dry ingredients into the wet ingredients, just until mixed. Prepare a donut baking pan with non-stick cooking spray. Fill each hole of the pan with the batter. Transfer to the oven and bake for 12 minutes or remove when the edges start to brown. Set aside for 5 minutes before removing from pan. For the glaze: In a bowl mix the sugar, cream cheese, lemon juice, and water. Stir until smooth. Pour the mix into a piping bag and decorate the donuts. Serve and enjoy.