Preheat the oven to 350°F (175°C).
In a large bowl, combine the rolled oats, whole wheat flour, brown sugar, baking powder, and salt.
In a separate bowl, mix the unsweetened applesauce, honey, and vanilla extract.
Add the wet ingredients to the dry ingredients and stir until well combined.
Spread the mixture evenly into a greased 8x8-inch baking pan.
Spread the fruit jam or preserves evenly over the top of the oat mixture.
Bake for 20-25 minutes, or until the edges are lightly golden brown.
Allow the bars to cool completely before cutting into squares.
