Firm, crisp, and slightly sweet apples are best for this recipe. Apple varieties that work best for apple pie bars include Honeycrisp, Pink Lady, Golden Delicious, Gala, Jonagold, and Braeburn apples. Tart apples like Granny Smith apples are also great for apple pie bars as they hold up well when baked. Truthfully, you can use any variety of apples for this recipe! Use what you have on hand, or use a couple different types of apples to give the bars more flavor and dimension.