Preheat your oven to 350°F (175°C) and prepare an 8x8 inch baking dish by greasing it or lining it with parchment paper.

Toast the pecans in a small, dry skillet over medium heat for about 5-7 minutes, stirring frequently, until fragrant.

Chop the apples into small chunks, roughly 1/2 inch, and set aside to incorporate into the batter later.

Cream the butter and sugar in a mixing bowl until light and fluffy, about 2-3 minutes. Add in the egg, mixing until well combined.

In a separate bowl, whisk together the flour, baking powder, salt, and cinnamon. Gradually add this mixture to the creamed mixture, stirring gently.

Fold in the chopped apples and toasted pecans, mixing just until evenly distributed throughout the batter.

Spread the batter evenly into the prepared baking dish, pressing down firmly. Optionally, sprinkle extra apple pieces and pecans on top.

Bake in the preheated oven for 30-40 minutes or until the edges turn golden brown and a toothpick comes out clean.

Allow the bars to cool in the pan for at least 15 minutes before slicing into squares.