I will admit I haven’t made this particular pie gluten-free yet. However, it shouldn't be too difficult. The only ingredient that contains gluten in the entire pie is the plain flour. All you need to do is substitute plain flour for gluten-free plain flour. As mentioned previously, I haven't tested this myself yet so the results might not be optimal. I'll make sure to update this recipe as soon as I've tested out the gluten-free version. If you’re looking for tips on gluten-free baking, I recommend my friend Katarina’s blog The Loopy Whisk.