Raspberry Crumble Bars!

Fruity and delicious raspberry crumble bars with an oaty crumble base, raspberry filling, and even more delicious crumble on top!

Say hello to some of the most delicious bits of heaven you will ever eat… these raspberry crumble bars. They are HEAVENLY and just so incredibly moreish and scrumptious. Just one thing to know before you start, you do need to let them cool and then chill before slicing, and that little bit of patience is the secret to neat bars that hold together beautifully rather than crumbling apart!

Traybakes 

So yeah, another traybake to add to my never ending roster of bakes that I am always in love with. Honestly, if you have followed me for a while you will know that a traybake related bake is one of my favourite things ever and that’ll never change. 

Traybake can come in many a form, such as brownies, blondies, cookie bars, flapjacks and so on. These raspberry crumble bars are a new one to add to the list of goodness.

All of my traybake recipes, if I can help it, are made into a 9″ square tin. This is for ease, and so that I reduce the amount of bits and bobs you need to buy! I always use this traybake tin. 

Crumble

So we all know what a crumble is right? Its one of the most iconic classic things you can ever consume. I have varied crumble related bakes on my blog such as my apple crumble traybake, or even my apple crumble cupcakes.. but this one? Oh this is on another league. 

It isn’t quite ‘crumble’ to the idea of a classic dessert – but its a crumble like oaty delicious mixture of ingredients that create the best base and topping for these bars. 

• Oats – for this bake, I wanted an oaty flavour to come through to compliment the raspberries and also create a more textured crumble. 
• Flour – an obvious one, but plain flour is a must!
• Sugar – I decided to use light brown soft sugar, but this would work well with other sugars such as caster sugar, or even dark brown soft sugar. 
• Raising agents – this one may sound a little odd, but trust me – you want the tiny lift from the baking powder!
• Butter – I use unsalted butter as always, but a salted butter would work well also. I would avoid any baking spreads of margarines as they are too soft for the crumble mixture. 

Raspberries

The main part right? The raspberries! A delicious sweet and sharp mixture of heaven. I decided to not just add in some raspberries and hope for the best, and I didn’t just want to do a layer of jam as some recipes do… I wanted to level it up and make a mixture! 

• Raspberries – So for ease, I would recommend fresh berries. You need to be able to mash them up and frozen would make this too hard. You can try thawing frozen berries, but you would need to dispose of any excess liquid before using them. 
• Jam – A raspberry jam – a classic! Seedless, with seed, smooth, lumpy… whatever! 
• Lemon – The lemon is needed to cut through the sharpness of the raspberry but also bring out the flavour wonderfully. 
• Cornflour – A thickening agent in this case. Please use it, it’s much better than just using plain flour. 

It may sound silly in the method, but honestly the best way I found to make this filling was to add the ingredients to a bowl and mash them slightly with a potato masher. It meant I still had texture, but everything had mixed in well enough. 

Quick word on fresh versus frozen raspberries, because it really does matter here. Fresh is my first choice every time as they mash up easily and keep the filling lovely and thick. You can absolutely use frozen if that is what you have in, you just have to thaw them fully and drain off all that excess liquid first, otherwise the filling goes far too wet and your bars end up loose rather than holding together. I have popped the full little routine for frozen just below!

Fresh vs Frozen Raspberries for Raspberry Crumble Bars

I get asked about this a lot, so here is exactly how I would handle it. Fresh raspberries are ideal, but frozen work brilliantly too as long as you prep them properly first. Here is the routine I would follow:

1. Thaw them fully. Let them defrost completely at room temperature, or overnight in the fridge, so there are no icy bits left.
2. Drain off the liquid. Tip them into a sieve and let all of that reddish liquid drain away. This is the bit that saves your bars!
3. Give them a gentle press. Press them lightly with the back of a spoon to squeeze out any liquid still hiding in there, but don’t mush them to a purée, you still want some texture.
4. Then mix as normal. Add them to the bowl with the jam, lemon and cornflour and mash slightly, exactly like you would with fresh.

The whole point of the draining is getting rid of that extra water. Skip it and the filling goes too wet, which stops the bars setting and leaves you with a soggy middle. A couple of minutes over the sieve and you are golden!

Assembling the bars

As you can see from the photos there are layers to these raspberry crumble bars. It’s fairly simply though – a majority of the crumble mix goes into the lined 9×9″ square tin and you press it down firmly. I found 500g of the crumble mix was perfect for this layer after some experimenting with ratios. 

Then, you top the base with the mashed raspberry mix and spread evenly, and then sprinkle over the rest of the crumble mix. This part of the crumble mix doesn’t need pressing down as it would turn into a raspberry mush. 

Baking the bars

For a bake like this, and basically any bake ever unless stated otherwise, you need a preheated oven. Here are the temperatures so you can find yours at a glance:

• Fan: 180ºc
• Conventional: 200ºc
• Gas mark: 6
• Fahrenheit: 400ºf

(I have a fan oven so I always bake this one on the fan setting, and I have honestly never baked in a gas oven myself!)

The temperature is slightly higher compared to other traybake recipes I have done, but you want the extra warmth to really start toasting and baking the crumble mix and it really helps.

Now, how do you know when they are actually done? Two things to look for. First, the crumble on top wants to be golden brown all over, not still pale and blonde in the middle. Second, the raspberry filling should look visibly thickened and be bubbling away at the edges rather than sitting there loose and watery. When the top is properly golden and the filling is bubbling, you are there. Do remember they firm up a LOT as they cool and chill, so a slightly soft middle straight out of the oven is completely normal and nothing to worry about!

Tips and Tricks

So when it comes to making a bake like this, it is surprisingly easy, but there are ways to help make sure it works wonderfully. When making the crumble mix I simply use a large bowl, add the ingredients, and rub them together with my fingertips. This means you can still have the wonderful texture of the oats in the crumble without accidentally destroying them in a food processor or mixer.

For the raspberry mix, I genuinely just use another bowl and a potato masher – but a large spoon or fork works well, it just takes a bit longer. You don’t want to over mix this either as you want texture to the mixture. 

As mentioned above, I use this traybake tin as its the perfect size. 

One last thing, and honestly it is the most important tip for neat bars: give them proper time to cool and set before you slice. I let mine cool completely in the tin first, and then I pop the whole thing into the fridge for at least 2 to 3 hours (overnight is even better!). Warm bars will squish and crumble the second you cut into them, but a properly chilled slab cuts into lovely clean, sharp squares every single time. Use a sharp knife and wipe it clean between cuts, and you will get those neat edges you see in the photos.

Storage and Freezing Raspberry Crumble Bars

Right, let’s talk about keeping these beauties, because they store really well and freeze like an absolute dream.

At room temperature: they are fine in an airtight container at cool room temperature for a day or so, but because of the fresh fruit filling I honestly prefer to keep mine in the fridge.

In the fridge: pop them into an airtight container and they will keep happily for up to 4 to 5 days. The cold also keeps them lovely and firm, which makes them even easier to slice and eat.

In the freezer: these freeze brilliantly! Once they are fully cooled and sliced, freeze the bars in an airtight container, layered with a little parchment so they don’t stick together, for up to 3 months. To eat, just let them thaw at room temperature for a few hours, or overnight in the fridge, and they are as good as fresh. This is exactly why I love making a big batch, you always have a little raspberry something waiting for you!