Peeling the Peaches:
Bring a large pot of water to a boil.
Prepare an ice water bath in a large bowl.
Score a small, shallow “X” on the bottom of each peach.
Submerge the peaches in the boiling water for 30-60 seconds.
Remove the peaches and place them in the ice water bath.
After cooling, peel off the loosened skin starting from where you scored the “X.”
Gluten Free Lemon Shortbread:
Adjust the oven rack to the lower middle position and preheat to 375ºF (190ºC). Line a 9-inch (23cm) square baking pan with parchment paper.
In a large bowl, rub the lemon zest into the sugar using your fingertips.
Add the softened butter and vanilla, and mix well with a wooden spoon or rubber spatula until combined.
In a separate bowl, whisk together the gluten free flour blend, xanthan gum, and salt.
Combine the dry ingredients with the butter-sugar mixture, mixing until clumpy. Knead until a crumbly dough forms.
Peach Filling:
Slice the peaches into ½-inch (1-1.5cm) thick wedges.
Toss the peach slices in a large bowl with sugar, cornstarch, lemon juice, and vanilla.
Assembling & Baking:
Press about ⅔ of the shortbread dough (about 390g) into the lined baking pan, smoothing it into an even layer.
Layer the peach filling evenly over the shortbread base. Drizzle over any remaining juices.
Crumble the remaining ⅓ of the shortbread dough over the peach filling, leaving some peaches visible.
Bake for 50-55 minutes until the crumble is light golden brown and juices are bubbling through the topping.
Cool completely before removing from the pan and slicing into bars. For cleaner slices, chill in the fridge for 30 minutes before cutting.
Storage:
Store the bars in a closed container in a cool, dry place or in the fridge for 3-4 days. Note that the crust and crumble will soften slightly over time.