Preheat oven to 350°F.
Lightly grease an 8”x8” baking dish.
Using an electric mixer, beat together butter, brown sugar and cinnamon for 3-4 minutes, or until mixture is light and fluffy.
Add flour and baking powder and mix for 1-2 minutes, or until mixture resembles coarse crumbs.
Remove 1 cup of crust mixture and set aside. Press remaining crust mixture into an even layer on the bottom of the prepared baking pan.
Bake for 12-14 minutes, or until light golden brown in color.
While the crust is baking, make the filling. Using a large bowl, add flour, cornstarch, brown sugar and cinnamon; stir until well combined.
Add the diced peaches and toss until well combined.
Spread the filling mixture on top of the baked crust. Sprinkle the chopped pecans evenly on top.
Crumble the 1 cup of reserved crust mixture on top of filling.
Bake for 35-40 minutes, or until crust topping is golden brown in color.
Let pan cool completely before slicing into bars with a sharp knife.
Note: I did not peel the peaches, but you could certainly peel them if you’d like. I do recommend using fresh peaches for this recipe. There are a lot of peaches in these bars, and canned peaches won’t produce the same flavor.