In a large bowl, mix together the applesauce, sugar, and egg white until well combined.

In a separate bowl, whisk together the whole wheat flour, oat bran, all-purpose flour, salt, and baking powder.

Gradually add the dry ingredients to the wet ingredients, mixing until a dough forms.

Add milk and vanilla extract to the dough and mix well with your hands until a ball forms.

Cover the bowl and refrigerate the dough for 1-2 hours to allow it to chill and become easier to handle.

After chilling, divide the dough into 16 equal-sized small balls.

On a lightly floured surface, roll out each ball into a circle approximately 3.5 inches in diameter. Be sure to use extra flour as the dough is sticky.

Place one heaping teaspoon of fruit preserves or pie filling in the center of each circle.

To form the traditional hamantaschen triangle, fold over the edges of the circle and pinch to create three corners. Leave a small amount of the filling uncovered in the center.

Preheat your oven to 375°F (190°C).

Place the formed hamantaschen cookies on a sprayed cookie sheet.

Bake in the preheated oven for 10-15 minutes, or until the cookies are golden brown.