Almond Flour instead of regular flour

Consider, too, that the flour in the crumble topping serves to soak up some of the juices in the cooked fruit, and binds with the fat in the topping to give an almost cookie-like quality to it, which makes the topping so appealing.

If you don't have a GF blend on hand, you could blitz oatmeal in a food processor to a fine powder. Looking at the recipe, the ratio of flour to the other ingredients in the streusel topping seems a bit high. If I were adapting this, I'd dial the flour substitute back a bit, using maybe 140 - 150 grams all told.

The King Arthur almond flour that I use doesn't have a strong almond flavor (plus, I kind of like the combination of pistachios and almonds) so I'd probably use about 30 or 40 grams of that, with the balance being either blitzed oats or a GF blend (an ingredient I don't always have on hand) or a combination. ;o)

I agree with Happygoin. You want to highlight those delicious pistachios. I have to bake gluten free frequently as well, and want to recommend Cup4Cup as the gluten free flour that I’ve had the most success with. It can be hard to find, and Bob's Red Mill is a close second.

Thanks! Great suggestion.

I’m sure it would taste good, but it would be a shame to use expensive pistachios and then have them compete with the almonds for attention.

I think I’d opt for a gluten free baking flour.