Start by preheating your oven to 350°F (175°C). This ensures that your donuts bake evenly and turn out perfectly fluffy.
Lightly grease your donut pan with cooking spray or a little oil to prevent sticking. Set it aside.
In a large mixing bowl, whisk together the whole wheat pastry flour, almond flour, baking powder, baking soda, cinnamon, and salt until well combined.
In another bowl, beat the eggs. Then add the mashed bananas, applesauce, maple syrup, and vanilla extract. Mix until smooth and well blended.
Pour the wet mixture into the dry ingredients. Gently fold them together using a spatula until just combined. Be careful not to overmix; a few lumps are okay!
Spoon the batter into the prepared donut pan, filling each cavity about two-thirds full. This allows room for the donuts to rise without overflowing.
Place the donut pan in the preheated oven and bake for 12-15 minutes, or until a toothpick inserted into the center comes out clean. The tops should be lightly golden.
Once baked, remove the donut pan from the oven and let it cool for a few minutes. Then, gently transfer the donuts to a cooling rack. While they cool, you can prepare the glaze.
In a small bowl, mix the confectioners style erythritol (or powdered sugar), milk, and vanilla extract until smooth. Adjust the consistency by adding more milk if needed.
Once the donuts are completely cool, dip the tops into the glaze or drizzle it over them. Allow the glaze to set for a few minutes before serving.