Preheat the oven to 350℉ (176℃) and spray a 9x13-inch baking dish with non-stick cooking spray.
In a large bowl mix together the key lime pie filling and angel food cake mix using a spoon or spatula. Mix gently until just combined.
Pour the batter into the prepared baking dish and spread it evenly.
Place the baking dish in the oven on the center rack. Bake for 20-25 minutes or until the top starts to brown. Check for doneness by interesting a toothpick into the center, it should come out clean.
Remove the pie bars from the oven and place on a cooling rack. Allow the pie bars to cool completely, about 1 hour.
Slice the pie bars into squares and dust with powdered sugar. Serve and enjoy!
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Notes
How to serve:
Add whipped cream or cream cheese frosting to the completely cooled bars for a touch of creaminess.
Add fresh lime zest to the freshly baked bars or a squeeze of fresh key lime juice before dusting with powdered sugar for extra tanginess.