Gluten Free Peach Crumble Bars

These gluten free peach crumble bars combine a buttery lemon shortbread with a juicy peach filling. They’re incredibly easy to make and they’re absolutely heavenly served with a dollop of vanilla ice cream. And you’d never know that they’re both gluten and egg free!!

If you want to make the most of the peach season this year, you need to make these gluten free peach crumble bars. And I don’t mean just once. Make them again and again and again. Because they’re INCREDIBLE and they also disappear way too quickly.

The combination of the buttery lemon shortbread with the juicy peach filling is ridiculously good, and they’re also super easy to prepare. They’re also the perfect dessert for anyone who can’t eat gluten and/or eggs – but, honestly, absolutely EVERYONE will love them.

Here’s why you’ll love these gluten free peach crumble bars 

• The buttery, melt-in-the-mouth (gluten free!!) lemon shortbread. It’s wonderfully rich and delicate, with just the right balance between crisp and crumbly. The shortbread is packed full of lemon zest and vanilla, and it’s not too sweet, because we need to take into account the sweetness of the filling as well.
• The juicy peach filling. I packed A LOT of filling into these crumble bars: there are five peaches in there, which results in just the right proportion of filling to shortbread. The texture of the filling is absolutely spot on: it’s juicy without being too runny, and the peaches are soft without being mushy – they still have a bit of texture to them.
• Super easy to make. These crumble bars are really incredibly straightforward to prepare, and you don’t need any special equipment (no stand or hand mixer or anything like that).
• You’d never know that they’re gluten free!! I made sure to optimise the recipe so that the bars aren’t too crumbly, which can sometimes happen with gluten free recipes. Instead, they’re just crumbly enough so that they simply melt in your mouth, but they’re also sturdy enough so that you can slice them and pick them up without worrying about them crumbling all over the place.
• And they’re egg free as well! Because the bottom crust and the crumble on top are both based on a simple shortbread dough, you don’t need to use any eggs in this recipe.

The buttery shortbread crust & crumble

You’ll use the same shortbread cookie dough for both the bottom crust and the crumble topping, which makes this recipe super straightforward.

Here are my top tips for making the lemon shortbread dough:

• Use unwaxed (ideally organic) lemons. Because you’ll be using lots of lemon zest, I recommend using organic unwaxed lemons – that will give you the best flavour and you’ll also avoid any pesticides or fungicides that the “regular” lemons are treated with.
• Rub the lemon zest into the sugar. This helps to release the maximum amount of essential oils from the lemon zest, which will make your crumble bars extra fragrant.
• For best results, weigh your ingredients, especially the flour. If you’re using cups/volume measurements, it’s very easy to over-measure your flour (especially because different brands of gluten free flour blends can vary A LOT in terms of density). Too much flour can make these crumble bars too dry and crumbly – so, to get the best possible texture, I recommend using a digital food scale.
• No raising agents. I don’t use any chemical raising agents (baking powder or baking soda) in my shortbread dough because that can make it too delicate and crumbly.
• No need to bake the bottom crust separately before you add the peach filling. Typically, when you’re adding any kind of (fresh or frozen) fruit to crumble bars, it’s best to partially bake the bottom crust before you add the fruit: this prevents the crust from becoming wet or soggy from the moisture released by the fruit. But that’s not the case here. You can assemble the bars completely and bake all the elements together, which makes the whole process much easier and quicker – and your final bars will still have a perfectly buttery and crisp bottom crust. The trick is to get your baking process just right, but more on that below!

The juicy peach filling

I actually used the same peach filling as in my gluten free peach galette – that one was absolutely INCREDIBLE, and why mess with perfection? In terms of ingredients, the filling couldn’t be simpler: thickly sliced peaches, some sugar, a squeeze of lemon juice, a generous dash of vanilla and cornstarch for thickening.

A few things to keep in mind with the filling:

• When selecting your peaches, make sure that they’re not overly ripe. You want them to be flavourful and juicy, but not too soft, otherwise they’ll turn to mush in the oven.
• You can peel your peaches or use them with their skin on. The recipe below includes all the instructions for peeling them, which is incredibly straightforward. Both options (peeled and skin-on) work great, so just go with whichever one you prefer!
• You don’t need a lot of sugar in the filling: 75g (¼ cup + 2 tablespoons) is more than enough. The shortbread crust and crumble themselves are already sweet, so there’s no need to add a lot of sugar to the peaches.
• The lemon juice and vanilla really amp up the peach flavour. The lemon juice also adds a bit of acidity, which balances out the sweetness and gives a more well-rounded dessert.
• The cornstarch thickens the peach juices and prevents the filling from being too runny. For the cornstarch to achieve its full thickening power, it’s important that the juices come to a boil in the oven: the crumble bars are properly baked once you see bubbles popping up through the crumble topping (not just around the edges but in the centre as well).
• Toss the sliced peaches with the sugar and other ingredients *just before* you assemble the crumble bars. If you prepare the filling too far in advance, the peaches will release A LOT of juice, which can make the bottom shortbread crust a bit soggy – something you definitely want to avoid!

Top tips for assembling & baking the gluten free peach crumble bars

• Use about ⅔ of the shortbread dough for the bottom crust, and crumble the remaining ⅓ over the peach filling. This will give you a bottom crust that’s thick enough to give you nicely sturdy bars that you can easily pick up without them being too delicate or too crumbly. At the same time, the crumble topping doesn’t cover the filling completely – it allows some of it to peek through, which serves two purposes: (1) it makes the crumble bars even prettier and (2) it allows some of the moisture from the peach filling to evaporate, which prevents the bars from being too wet or soggy.
• Bake at 375ºF/190ºC on the lower middle oven rack. This ensures that the bottom crust will be fully baked through and nicely crisp even if you don’t par-bake it separately. 
• Bake the crumble bars until you can see the juices in the filling visibly bubbling (not just around the edges but in the centre as well). That means that the juices have come to a boil and the cornstarch has reached its full thickening power – and that, in turn, means that the filling won’t be too runny and that there won’t be any excess moisture that could make your shortbread crust soggy or too soft.
• Allow the bars to cool completely to room temperature and then chill them in the fridge for at least 30 minutes before you remove them out of the baking tin and slice them into individual portions. While they’re warm, the bars will be quite fragile. It’s important that they cool completely before you slice them, otherwise you’ll be left with a (delicious) mess. The short chilling time firms up the shortbread crust even further, and makes the bars nicely sturdy so you can cut them into neat slices.

Listen, I know that letting the crumble bars cool completely and then chilling them for a further 30 minutes in the fridge can be tough. It’s probably the most difficult part of the recipe!

So, if you run out of patience, and slice into them while they’re still warm: been there, done that and, honestly, I have zero regrets about it. A warm peach crumble bar with a scoop of vanilla ice cream on top is seriously HEAVENLY. And when something tastes *that* good, who cares if it’s a bit messy.

Happy baking!