Preheat your oven to 350°F (175°C). Generously grease a 9x13-inch baking dish with non-stick cooking spray.

In a large mixing bowl, combine the dry angel food cake mix and the entire can of lemon pie filling.

Using a stainless steel spatula, gently fold the two ingredients together until just combined and no large pockets of dry powder remain. The batter will be thick and slightly foamy.

Spread the batter evenly into your prepared baking dish, smoothing out the top.

Bake on the center rack for 20 to 25 minutes, or until the edges pull away slightly from the pan and the top is lightly golden.

Remove from the oven and let the bars cool completely at room temperature.

Once fully cooled, use a fine mesh sieve to generously dust the powdered sugar over the top. Slice into squares and serve!