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    Home » Recipes » Bars + Squares

    August 27, 2021 Bars + Squares

    Chocolate Oat Slice

    Jump to Recipe Print Recipe

    This Chocolate Oat Slice is so addictive, you will have to make a double batch. They’re rich and loaded with chocolatey flavour – perfect for an indulgent treat!

    3 flapjacks on a white plate

    I’ve never met a chocolate slice I didn’t like and this one is no exception. They are chewy and crisp at the same time and I’m not ashamed to admit that they don’t last long in our house!

    This chocolate oat slice are full of butter, cocoa and oats with a hint of golden syrup and a generous drizzle of chocolate on top to give you double the cocoa flavour!

    You can make these chocolatey oat bars in under 30 minutes, and they make a wonderfully indulgent treat with a cup of tea. 

    oat slice in a cake tin on a baking rack with a blue napkin underneath

    What you’ll need to make this recipe

    11 x 7” rectangle cake tin

    Parchment paper to line the tin

    Quick cooking oats – make sure not to use the regular kind, you want to use the quick cooking ones here

    Unsalted Butter

    Sugar – I like to use a mix of white granulated sugar and demerara sugar to give more of a toffee flavour

    Golden Syrup – this syrup also adds to the toffee flavour.  I’ve noted alternatives to using the syrup below in my notes section.

    Flour – the flour helps to bind everything together

    Cocoa powder – a couple of tablespoons stirred into the mixture gives your flapjacks a chocolatey flavour.

    Chocolate (milk, dark, or white) for drizzling over at the end.

    jar of Lyle's Golden Syrup
    Lyle’s Golden Syrup

    How to Make this Chocolate Oat Slice

    1. Heat your oven to 375F/190C and spray your cake tin with non-stick cooking spray and lining with parchment paper making sure to leave an overhang of paper on two sides to make it easier for you to lift the flapjacks out of the tin.  Alternatively, you can also use butter to grease your tins if, you prefer.
    2. In a medium sized pot, melt the butter slowly over low heat. Next, add the sugar and heat until the sugar has melted, and everything is combined.  Remove the pot from the heat and let the mixture cool slightly.
    3. Measure out the other ingredients (except for the chocolate) and add them to the pot with the butter and sugar. Lastly, give everything a good stir with a wooden spoon until combined.
    4. Tip the mixture into your prepared tin and spread it out evenly.  I like to use an offset spatula for this job, but you can use a wooden spoon, a knife, or a fork.  Whatever works best for you.  You might think there isn’t enough mixture to cover the entire pan, but I assure you that if you keep going, you’ll be able to make a thin layer across the bottom of the entire pan.
    5. Bake the flapjacks on the middle rack of the oven for 15 – 20 minutes.  In my oven, they are usually ready at around 17 minutes.  As they’re cooking, the butter will bubble up and then settle back down once the flapjacks cool down.
    6. Let the flapjacks cool in the tin for 10 minutes and then transfer to a cutting board and cut into 16 triangles.  You can also cut them into squares if you prefer.  Allow to cool completely.
    7. Melt the chocolate until runny.  I use a microwave set at 50% power using 20 second intervals for this job.  After each 20 second set, I stir the chocolate with a fork.  It usually takes about 3 sets of 20 second bursts for my chocolate to melt.  Alternatively, you can melt the chocolate slowly over a double boiler on the stove.
    8. Using a fork, spool, pastry bag, or piping bottle, drizzle the melted chocolate over the cooled flapjacks and allow to harden at room temperature.  If you’re in a hurry, you can also pop them into the fridge for 30 minutes.
    baked chocolate oat slice cut into wedges on a wooden cutting board

    Storage

    The chocolate oat slices will keep well in an airtight container at room temperature for 5 days.

    Julianne’s Notes

  • What can I use instead of golden syrup?
  • I was lucky enough to find golden syrup in my local Canadian Walmart in the British foods section.  If I was describing the flavour, I would say that it has almost a slight burnt sugar flavour.  A bit like toffee. 

    For those of you who are unable to get your hands on some of this syrup, you can substitute it with honey, golden corn syrup or maple syrup.  The flavour of these syrups is different from that of golden syrup, but not so much so that it will drastically change the taste of your flapjacks.  The texture of the flapjacks should remain the same.

    What other flavours can I add to my chocolate slice?

    You can leave the cocoa out of the recipe to make a plain oat slice which is the traditional way.  Other flavours you might want to try try mixing in include:  peanut butter, coconut, ginger, and fruit jams.

    What do I do if my oat slice is hard and crumbly?

    If you let your slice bake too long, they run the risk of becoming too hard and crumbly for cutting into neat wedges.  There isn’t really a way to soften them up at this stage, so my suggestion would be to crush the flapjacks and use them as a topping for ice cream.

    2 chocolate flapjacks on a white plate

    Check out these recipes for other bars and squares:

    Chocolate Toffee Bars

    Biscoff Millionaires ‘Shortbread’

    Share your baking!

    If you make this chocolate slice recipe, be sure to leave a comment.  I love hearing from you!  Also, if you make this recipe, I’d love for you to share your photos on Instagram.  Don’t forget to use the hashtag #bakersbookshelf.

    3 chocolate oat slice on a white plate

    This chocolate oat slice offers the comfort of a traditional oat bar with the added indulgence of a double chocolate kick!

    2 chocolate flapjacks on a white plate
    Print Recipe
    5 from 1 vote

    Chocolate Oat Slice

    This oat slice is full of butter, cocoa and oats with a hint of golden syrup and a generous drizzle of chocolate on top to give you double the cocoa flavour!
    Prep Time10 minutes mins
    Cook Time20 minutes mins
    Cooling Time30 minutes mins
    Course: Dessert
    Servings: 16 pieces

    Equipment

    • 11 x 7" rectangular cake tin

    Ingredients

    • ⅔ cup unsalted butter (150 g)
    • ⅔ cup quick cooking oats (150 g)
    • Pinch salt
    • ¼ cup granulated white sugar (50 g)
    • ¼ cup demerara sugar (or light brown sugar) (50g)
    • ⅓ cup flour (50 g)
    • 1 tablespoon golden syrup (or honey, maple syrup or corn syrup)
    • 2 tablespoons cocoa powder, non sweetened
    • 1 cup milk chocolate, melted for drizzling over the top

    Instructions

    • Heat your oven to 375F/190C and spray your cake tin with non-stick cooking spray and lining with parchment paper making sure to leave an overhang of paper on two sides to make it easier for you to lift the flapjacks out of the tin. You can also use butter to grease your tins if, you prefer.
    • In a medium sized pot, melt the butter slowly over low heat. Add the sugar and heat until the sugar has melted, and everything is combined.  Remove the pot from the heat and let the mixture cool slightly.
    • Measure out the other ingredients, (except for the chocolate), and add them to the pot with the butter and sugar. Give everything a good stir with a wooden spoon until combined.
    • Tip the mixture into your prepared tin and spread it out evenly.  I like to use an offset spatula for this job, but you can use a wooden spoon, a knife, ora fork.  Whatever works best for you.  You might think there isn’t enough mixture to cover the entire pan, but I assure you that if you keep going, you’ll be able to make a thin layer across the bottom of the entire pan.
    • Bake the flapjacks on the middle rack of the oven for 15 – 20 minutes.  In my oven, they are usually ready at around 17 minutes.  As they’re cooking, the butter will bubble up and then settle back down once the flapjacks cool down.
    • Let the flapjacks cool in the tin for 10 minutes and then transfer to a cutting board and cut into 16 triangles.  You can also cut them into squares if you prefer.  Allow to cool completely.
    • Melt the chocolate until runny.  I use a microwave set at 50% power using 20second intervals for this job.  After each 20 second set, I stir the chocolate with a fork.  It usually takes about 3 sets of 20 second bursts for my chocolate to melt. Alternatively, you can melt the chocolate slowly over a double boiler on the stove.
    • Using a fork, spool, pastry bag, or piping bottle, drizzle the melted chocolate over the cooled flapjacks and allow to harden at room temperature.  If you’re in a hurry, you can also pop them into the fridge for 30 minutes.

    Notes

    Storage
    The flapjacks will keep well in an airtight container at room temperature for 5 days.
    This recipe was adapted from a Flapjack recipe I found in a recipe book produced by Northern Ireland Hospice ‘100 Recipes: Contributed recipes for tray bakes, biscuits, and desserts'(4th Edition, 2008).

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    Reader Interactions

    Comments

    1. Dominique says

      July 09, 2022 at 3:30 am

      5 stars
      I just came here to say that these oat slices are so addictive! My husband asks me to make them all the time!

      Reply

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