Our creamy Thermomix Lemon Crumble Slice is the most delicious sweet treat with layers of crunchy oat crumble and a zesty lemon filling!
This Thermomix Lemon Crumble Slice recipe is one of the oldest recipes on our website... and one of our most popular!
This cafe-style slice looks impressive - but it's actually SO simple to make!
Serve it for morning tea, as a lunchbox treat or warm it up for a decadent dessert.
Lets get baking...
Why You're Going To Love This Recipe
Once you try our Thermomix Lemon Crumble Slice, we guarantee it will become a firm favourite:
- Cafe-Style - this slice looks (and tastes) like it should belong in a cafe... and yet its SO easy to make.
- Basic Ingredients - this slice is made entirely from basic pantry and fridge staples.
- Suitable For All Thermomix Models - whether you have a TM31, a TM5 or a TM6, you can make this delicious lemon slice!
- Freezer-Friendly - freeze any leftover slice for up to 3 months. Allow to defrost in the fridge before consuming.
What You Need
Head to your pantry and fridge and you'll find that you already have most (if not all!) of the required ingredients.
Please scroll to the recipe card at the bottom of the post for ingredient quantities and the full detailed method.
For The Crumble
- Butter - you can use salted or unsalted butter in this recipe. If using salted butter, omit the pinch of salt in the ingredients.
- Vanilla Extract - or vanilla essence
- Flour - use plain all-purpose flour
- Rolled Oats - also known as old fashioned oats. You can substitute the rolled oats for quick oats if you prefer.
- Salt - omit if using salted butter.
- Bi-Carbonate of Soda - also known as baking soda.
- Brown Sugar - regular or dark brown sugar can be used.
- Raw Sugar - for added crunch!
For The Creamy Lemon Filling
- Lemon Zest - use only the yellow part of the skin (not the white).
- Sweetened Condensed Milk - it's best to use full fat (not skim) sweetened condensed milk.
- Lemon Juice - freshly squeezed.
- Egg Yolks - we only require yolks - so keep your egg whites aside and make meringue or pavlova!
- Lemon Extract - optional. This gives the filling a stronger lemon flavour but is entirely optional.
Step By Step Instructions
You won't believe how easy it is to make creamy lemon crumble slice in your Thermomix!
Please scroll to the recipe card at the bottom of the post for ingredient quantities and the full detailed method.
Step 1 - Make The Oat Crumble
Melt the butter and vanilla extract in the Thermomix bowl.
Add the plain flour, rolled oats, pinch of salt, bi-carbonate of soda, brown sugar and sugar sugar and mix until combined.
Press half of the oat crumble into the base of a lined slice tin and bake for 15 minutes or until golden.
Set aside.
Step 2 - Make The Lemon Filling
Grate the lemon zest in the Thermomix bowl until very finely grated.
Add the sweetened condensed milk, egg yolks, lemon juice and lemon extract (optional).
Mix to combine.
Pour the lemon filling over the cooked base.
Step 3 - Bake
Sprinkle the remaining oat crumble over the lemon filling.
Bake for 23-26 minutes or until lightly golden.
Allow to cool before placing into the fridge overnight.
Expert Tips
Follow our simple tips for the most delicious Thermomix Lemon Crumble Slice:
- you can use salted or unsalted butter in this recipe. If using salted butter, omit the extra pinch of salt.
- lemon extract is entirely optional - it gives the lemon filling a stronger lemon flavour but can be omitted.
- use the leftover egg whites to make meringue, pavlova or chocolate mousse.
- chilling the slice in the fridge overnight will make it easy to cut the slice into pieces.
- store leftover slice in an airtight container in the fridge for up to 1 week.
- freeze any leftover slice for up to 3 months. Allow to defrost in the fridge before consuming.
FAQs
No! The lemon extract is entirely optional. It gives the filling a stronger lemon flavour, but can be omitted. Alternatively, you can use extra lemon zest for a stronger lemon taste.
Yes! Our recipe is suitable for use in all Thermomix models.
Related Recipes
Looking for some more delicious Thermomix slice recipes?
We have plenty!
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There's everything from family dinners to kids snacks, desserts to cookies, slices to Christmas recipes, cocktails to chocolate recipes and more!
Thermomix Lemon Crumble Slice
Equipment
- Thermomix
- Oven
- 18cm X 28cm baking tin
Ingredients
- 170 g butter see tips
- 1 teaspoon vanilla extract
- 155 g plain flour
- 110 g rolled oats
- ½ teaspoon salt
- ½ teaspoon bi-carbonate of soda
- 80 g brown sugar
- 100 g raw sugar
- 1 tablespoon zest from one lemon peeled
- 395 g sweetened condensed milk
- 80 g fresh lemon juice
- 2 egg yolks
- ½ teaspoon lemon extract optional
Instructions
- Preheat oven to 160 degrees celsius (fan-forced).Grease and line an 18X28cm slice tray with baking paper, allowing the edges to overhang.
- Melt the butter and vanilla in the Thermomix bowl for 2 minutes, 80 degrees, Speed 2. Scrape down the sides of the bowl.
- Add the plain flour, rolled oats, salt, bi-carbonate of soda, brown sugar and raw sugar. Mix for 20 seconds, Reverse, Speed 2. Scrape down the sides.Mix for a further 20 seconds, Reverse, Speed 2 or until combined.
- Spread half of the crumb mixture into the bottom of the prepared tray and press firmly into an even layer.
- Bake in the preheated oven for 15 minutes or until lightly golden.
- Remove from oven and set aside (leave the oven turned on).
- Place the peeled zest of 1 lemon into the Thermomix bowl. Grate for 20 seconds, Speed 6.Scrape the sides of the bowl. Repeat until you have a very finely grated zest.
- Add the sweetened condensed milk, lemon juice, egg yolks and lemon extract (if using) and mix for 30 seconds, Speed 4.Scrape the sides of the bowl and mix for a further 30 seconds, Speed 4.
- Pour the mixture over the baked crumb crust in the baking dish and spread into an even layer.
- Sprinkle the remaining crumble mixture over the top of the lemon layer.
- Bake in oven for 23 – 26 minutes or until lightly golden.
- Remove from oven and allow to cool.
- Cover and refrigerate for at least 2 hours (preferably overnight) then take it out and cut into squares.
- Store in airtight container in the refrigerator for up to 1 week.
Notes
- you can use salted or unsalted butter in this recipe. If using salted butter, omit the extra pinch of salt.
- lemon extract is entirely optional - it gives the lemon filling a stronger lemon flavour but can be omitted.
- use the leftover egg whites to make meringue, pavlova or chocolate mousse.
- chilling the slice in the fridge overnight will make it easy to cut the slice into pieces.
- store leftover slice in an airtight container in the fridge for up to 1 week.
- freeze any leftover slice for up to 3 months. Allow to defrost in the fridge before consuming.
Di White - Mixing From Scratch says
This was lovely! Made to share, and everyone loved it. The lemon was perfect, no additional extract required. Many commented that it was like lemon cheesecake. Very generous portions too.
Amelia says
Was nice, just way too sweet. I feel like the sugar could be halved.
Amelia says
Apologies, accidentally pressed 3 was meant to be a 5 ⭐️
Anthony says
I entered this into a bake off and it won!
Lucy says
Fantastic!
Trudy says
Can this be served warm?
Lucy says
Absolutely!
Sarah says
Have made this soooo many times, it’s my go to slice. I add a touch more lemon and less sugar to suit my taste and leave out the lemon extract. Love how all ingredients are such staple pantry items for me and I get to use my fresh lemons.
Lucy says
Fantastic!!!!
Anita says
I made this for a family party and got SOO many compliments. It really was delicious! I didn’t have lemon extract though, just added an extra splash of lemon juice. Highly recommend this slice!
Lucy says
Fantastic!!
Jess says
Looks lovely, any idea who long in the fridge? I like to use these sorts of Slices for lunch boxes.
Lucy says
Hi Jess, it will be fine for up to 5 days in the fridge.
Sally says
How can I make the slice gluten free?
Sandy says
Can you please tell me if this slice is suitable to freeze?
Lucy Mathieson says
I personally dont like to freeze this slice as I have found that the filling can go a bit runny when defrosted. That being said, I know other people who are happy freezing it!! xx
Shelley Elliott says
This recipe is delicious. Thank you.
Tammy Scott says
Can the oats for substituted for something else to make this Gluten Free?
Lucy Mathieson says
Hi Tammy, I'm not sure as this is the only way I've made it. You could try experimenting though!!
kandis says
I have made this 4 times. so good. i don't have lemon extract so skip it. still tastes great
Lauren says
That's excellent!
Kayann says
ok so I'm confused, at number 11 you say to spread half of the crumb mixture into the tray, are we then supposed to side aside the other half? or do we leave it in there & zest the lemon on top of it? The instructions aren't clear.
Lucy says
Yes you set the second half of the crumble mixture aside (as that is what you crumble over the top). The lemon zest forms part of the middle (the creamy portion).
Lucy says
I'm keen to try this. Has anyone tried with out the lemon extract?
Tessa - Down that Little Lane says
wowsers, just added the ingredients to my list to get this afternoon 🙂