Sourdough Caramel Slice

Sourdough caramel slice is something you just have to try! Ooey, gooey caramel layered on a sourdough shortbread based topped in chocolate. Does it get any better? I don't think so! You might be more familiar with Millionaire's shortbread. Caramel slice is essentially the same thing (perhaps the caramel is slightly less firm).

I make a batch of this sourdough caramel slice every single week. Actually, I make more than one because the first one almost always disappears! This slice also makes a lovely gift, so having a batch in the fridge is such a good idea!

Why You'll Love This Recipe!

Caramel - seriously, did I mention caramel? Enough said right? There's a reason they call it Millionaire's shortbread ... the caramel is so rich and decadent!

Upgrade Your Shortbread - if you love making and eating sourdough shortbread cookies, this is like a little upgrade on this recipe that makes the perfect indulgent treat or a special gift for family and friends. You might know it as Millionaire's shortbread.

Ingredients

• Butter - You'll need a 250g block of butter for this recipe. You'll use half for the sourdough shortbread base and half for the caramel filling. I've used salted butter, but you can use unsalted butter if you prefer.
• Brown Sugar - Again brown sugar is used in both the base and the filling. I don't recommend substituting any other type of sugar for this as you need the rich caramel flavors that only brown sugar can bring.
• Desiccated Coconut - this is added to the base and brings texture and flavor to the sourdough shortbread base. The coconut flavor compliments the caramel so well.
• All Purpose Flour - no need for bread flour here! All purpose will do just fine.
• Sourdough Starter - I've used sourdough starter, but you can use sourdough discard with no issues.
• Vanilla Extract - A little vanilla will help to bring out the caramel flavors and enhance the sweetness of the caramel filling in this recipe.
• Salt - adding a little salt to the filling is optional, but I like to add it as it cuts through the sweetness.
• Condensed Milk - Just a can of regular condensed milk.
• Chocolate Chips - I've topped this recipe with milk chocolate, but you can use semi sweet chocolate chips if you prefer. I find the milk chocolate works really well with the caramel, but of course you can adjust the chocolate selection to suit your personal taste preference.
• Vegetable Oil - the vegetable oil is optional, but it's a great way to stop the chocolate from cracking when you cut into it (or when you bite into it). You can use coconut oil if you prefer.

How To Make Sourdough Caramel Slice

Making sourdough caramel slice has 3 distinct steps. The sourdough shortbread base, the caramel centre and the chocolate topping. Each step is really easy to put together. I often make the base and caramel and then leave it in the refrigerator overnight before topping it with chocolate (usually because I get distracted with other things and forget to go back).

Preheat your oven to 160C (320F). Prepare an 8" x 12" slice pan by lining with parchment paper. Set this aside for the moment. I've tested this recipe so many times with different sized pans and this is the one that gives the best base to filling ratio.

Making the Base

Start by adding the melted butter to a medium sized mixing bowl (I generally just melt the butter in the microwave because it's the easiest way). To the melted butter, add the brown sugar, desiccated coconut, all purpose flour and sourdough starter. Mix together using a spatula. If the mixture is a bit stiff, I just use my hands to mush it together.

Tip the base mixture into the pan you prepared earlier and use your fingers to push the base mixture out until it covers the whole base of the pan. If you need to, use the base of a measuring cup or glass to flatten it out. You want to get it fairly even but it will flatten out a bit while it cooks.

It might seem like there's not enough base mixture, but be patient, it will spread out.

Place the base into the oven to cook at 160C (320F) for 10 minutes while you prepare the filling.

Prepare the Caramel Filling

To a medium saucepan, add the cubed butter, brown sugar, vanilla and salt if you're adding it. I always recommend cubing the butter because it melts more quickly. If you add a big chunk of butter, the sugar will start to caramelise and burn before the butter has fully melted, so take the time to cut the butter into cubes.

Gently melt the butter over a medium heat and whisk until it's all combined with the sugar and vanilla extract.

Once the mixture starts bubbling around the edges, pour in the can of condensed milk and whisk into the mixture keeping it over a medium heat.

Once the mixture is fully combined, allow it to warm through over medium heat, whisking fairly often to stop it catching on the bottom. You'll see that it will start to bubble quite a bit after a few minutes.

Once it starts to thicken and bubble, whisk the mixture continuously over a medium heat for around 4 to 5 minutes. If you feel it's getting too hot, turn the heat down or remove the saucepan from the heat for a minute. As long as you keep whisking it, it should be fine.

After 5 minutes of continuous whisking over medium heat, your caramel should be thick and glossy and darker in color. Remove from the heat. This should coincide with the base being baked through.

Assembling The Slice

Once the base has cooked, carefully remove it from the oven. Drop the oven temperature to 150C (300F).

Carefully pour the hot caramel over the base, using a spatula to spread the caramel fairly evenly.

Return the slice to the oven and cook for 10 minutes at 150C (300F). The caramel will bubble and that's ok. Let it cook.

Once 10 minutes is up, remove the sourdough caramel slice from the oven and allow it to sit and cool for 10 minutes before placing into the fridge (ensuring that you have it sitting on a board or something to protect the shelf in your fridge).

Chocolate Topping

Once the caramel is set (usually takes around 2 hours) melt the chocolate. I put the chocolate chips in a bowl and microwave in 30 second increments until liquid (stirring in between each blast) but you can do this with a double boiler if you prefer.

Once the chocolate is melted, add the vegetable oil (if using) and stir well to combine. Pour melted chocolate over the top of the caramel, using an offset spatula to spread it all the way to the edges. You need to work quickly as the caramel will harden the chocolate quite fast.

Return the slice to the fridge for 10 minutes for the chocolate to fully set.

Recipe Tips

I've made this recipe hundreds of times (seriously it's something I make weekly for my family and it's my go to gift for pretty much everyone in my life). I even entered it in the Brunswick Agricultural Show (this is like the local county fair but it's the biggest one day show in the southern hemisphere) and won first prize! So trust me, I know how to make this recipe very well!

• Brown Sugar - don't substitute the sugar for anything else because you need the caramelisation for this recipe (it's caramel slice, right).
  
• Slicing - I recommend leaving the finished caramel slice at room temperature for around 10 minutes once the chocolate is set. This allows it to soften just enough for the chocolate not to crack when you slice it. You can run your knife under hot water, but this can smudge the chocolate (which is fine if you're not gifting it).
  
• Vegetable Oil - I know many people don't like using vegetable oil, but it does ensure the chocolate doesn't crack when you try to slice the sourdough caramel slice. You could use coconut oil if you prefer.
  
• Pecans - for something extra special, I love adding chopped pecans to the top of the melted chocolate before it sets. Pistachios are also a lovely idea for the holidays too!

How To Store + Freeze

One of the things I love most about this sourdough caramel slice is that it lasts a long time in the fridge. I only cut what I need so I store it uncut in the fridge for up to one month. I store it wrapped in parchment paper in an airtight container in the fridge. Once cut into squares I store for up to two weeks in the fridge (although it never actually lasts this long as someone always eats it).

You can freeze this sourdough caramel slice. Freeze it uncut in a large slab for up to 2 months. Thaw at room temperature.

Share the sourdough love!