The Best Sourdough Strawberry Crumble Bars

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Sweet strawberry filling sandwiched between a crisp shortbread base and crumble topping, these Sourdough Strawberry Crumble Bars are sure to be a hit with your family. A great recipe for using up sourdough discard, this slice uses basic ingredients and transforms them into a delicious treat!

Why You Need to Make this Recipe

• It’s nostalgic: This buttery, crumbly goodness, filled with juicy strawberries is the plain kind of comforting slice that Grandma used to make. It may not be super rich or decadent, but one bite of this will transport you straight to your childhood.
• It’s cheap to make: This sourdough strawberry crumble slice uses no specialty ingredients, which are easy to source and cheap to buy. Jam, flour, sugar, sourdough discard, butter, salt, and strawberries – a simple ingredient list indeed. If you’re wanting a snack without heading to the shop, you probably have all the ingredients to make this!
• Kids love it: sweet strawberry jam filling between a sweet shortbread base and a crumble topping – what’s not to love? I use this slice to get my boys to finish their dinner.

Ingredients You’ll Need:

This Sourdough Strawberry Crumble Slice uses humble ingredients that are inexpensive and easy to source. You probably have all of them in your pantry already! This recipe contains no eggs, baking powder or baking soda.

Sourdough Shortbread Base

A sweet, buttery shortbread base which is lightly crispy and chewy at the same time.

• Butter – the butter needs to be cubed and softened for this recipe, because it is going to be creamed.
• Sugar – I used a combination of golden raw sugar and white castor sugar for this recipe. I loved the golden hue it brought to the base and topping, plus the subtle caramel flavour that came through. Adding a browner hue of sugar will soften the shortbread, so if you are wanting a crisper base, then use 100% white sugar.
• Salt – this stops the shortbread base from blandness and emphasizes the sweetness
• Sourdough Discard – I love using up sourdough discard in surprising ways. Using it means that you could let the base mixture ferment a bit before baking. It will last in the fridge for up to 24 hours, meaning you could pre-mix the base for ease later on (and added benefits!)
• Flour – regular all-purpose flour is best for this recipe, but I used bread flour as always. This slice was still delectable!

Strawberry Conserve Filling

• Strawberries – 2 cups, sliced. Use fresh strawberries, or nothing. Frozen strawberries hold too much moisture and will result in a soggy slice – no one wants that! If you do not have strawberries, just use enough jam to cover the base, about 5mm thick,
• Berry Jam – The berry jam adds sweetness to the filling. You really need it, because the strawberries lose their punch if not sweetened. I used strawberry jam, but you could use any kind of red jam. If you are ditching the strawberries altogether, you could opt for an apricot or plum jam – delicious!

Sourdough Crumble Topping

• Butter, melted – the butter is melted in this part for ease of mixing. Only 1/4 cup is needed, as you do not need a large quantity of topping to cover the slice.
• Sugar – The crumble topping needs to be sweet, to balance the tartness of the berries and ensure that every layer adds pleasantness to the slice. 1/2 a cup should do the trick. Again, I used a mix of raw brown sugar and white castor sugar for the crumble topping. I would recommend using 100% sugar if you prefer a crisper crumble.
• Flour – All purpose flour is preferred, but bread flour is fine. There is no noticeable difference, in my humble opinion.
• Mixed Spice – 1 tsp will not make this mixture overwhelmingly spicy, but what it will do is accentuate the sugar and butter and deepen the overall flavour.
• Salt – If the crumble topping is bland, it won’t matter how sweet or buttery it is. Salt brings all the flavours together in perfect harmony.
• Sourdough Discard – a 1/4 cup sourdough discard helps to bind the ingredients and make it easier to mix. Again, adding sourdough means you could ferment this mixture if you’re worried about the white flour, but there is no need to do so if you’re pressed for time.

Equipment you’ll need

• 2 large mixing bowls – one to make both the base and the crumble topping (they use the same ingredients, so saves dishes), and one to make the strawberry filling.
• Wooden Spoon – I use a wooden spoon to cream my butter and sugar and do subsequent mixing. A bit of elbow grease is needed, but saves on dishes!
• Baking paper – This slice will stick otherwise! The baking paper needs to come out the sides of the flan dish, to easily lift the slice out.
• One large Flan dish – I like baking this in a 27 cm flan dish, because I could cut wedges of this slice and trick myself into thinking I was having pie. Otherwise, a 17 x 27 cm baking dish will do.
• Oven – because it needs to bake! This crumble slice has 2 rounds of baking, once with the base only, then a final bake to crisp everything up!

Making the Strawberry Crumble Slice

This Sourdough Strawberry Crumble Bars recipe is a 3 part recipe. Pre-bake the base, then top it with the strawberry and crumble layers, then put it back in the oven for a final bake. Let’s get into the nitty-gritty.

Making the Sourdough Base & Pre-bake

• Preheat the oven to 150 degrees Celsius. Line the flan dish with baking paper (screw up the baking paper, then unfurl it to get it to sit in the flan dish easily).
• Cube the butter and let the butter soften to room temperature.
• Add the sugar and salt to the butter. Cream until smooth and silky.
• Add the sourdough discard, and mix thoroughly to combine.
• Add the flour and bash it in until the mixture is holding together and there are no dry bits left.
• Press into the lined flan tin, then pop into the preheated oven to bake for 25 minutes. Note, this is just a pre-bake so that it cooks thoroughly and doesn’t get soggy. The base will still be soft at the end of 25 minutes.
• Remove from the oven and increase the temperature to 170 degrees Celsius.

Crafting the Strawberry Filling & Crumble Topping

• While the oven is heating up, prepare the strawberry filling. Slice the strawberries into a bowl.
• Add the jam, and stir to coat. Give it a taste, and add a bit more sugar or jam if it is not sweet enough. Set aside.
• I use the mixing bowl from the base mixture to make the crumble topping, since it uses basically the same ingredients, Saves dishes!
• For the crumble topping, mix together the flour, sugar, salt and mixed spice. Add the sourdough discard and melted butter and mix until there are no dry bits.

Assembling the Layers & Final Bake

• Spread the strawberry filling evenly over the cooled base.
• Crumble over the topping, being sure to completely cover the strawberry mixture while retaining large lumps (you’ll thank me later!)
• Pop into the oven, which should now be at 170 degrees Celsius, and bake for another 35 minutes.
• The Crumble topping should be nice and golden, and the strawberry filling bubbling away.

Serving Suggestions

While the Sourdough Strawberry Crumble Bars are pretty delicious on their own, they could be served in any way you would serve pie or apple crumble.

Custard, ice cream, whipped cream or yoghurt would be sublime on this yummy treat, slightly warmed.

Variations and Tips

• For these Sourdough Strawberry Crumble Bars, the golden raw sugar gave a lovely caramel flavour, but made the base a little softer. If you don’t want that, use 100% white sugar if you are wanting a crisper base and a crunchier topping.
• Start the base mixture and crumble mixture the day before, and leave in the fridge until ready to use. The sourdough will ferment the flour, making these bars easier to digest, plus it saves a lot of prep on the day you want to assemble and bake. I like to do things this way, because as a busy mama, there’s only so much time I can devote to a particular task.
• Skip the strawberries if they’re too expensive to source (we grow our own, so we have to think of ways to use them up!). Any kind of fresh berry would work, or you could just use plain jam or curd.