Low carb crumble topping without sugar or flour works in the Thermomix® only when the sweetener stays crystalline and the butter goes into the mixing bowl ice-cold. The moment either of those things melts, you no longer get crumbs but a compact almond-butter paste.
We have been making this crumble topping for years, whenever we need a topping for low carb cakes, apple bakes, or berry crumbles. The ratio of 120 g butter, 150 g ground almonds and 170 g xylitol is the point at which the crumbs get their typical crumble look without becoming sticky. If you cannot tolerate xylitol, you can switch to erythritol. More on that below.
Low Carb Crumble Topping, Thermomix®
Ingredients 0 / 3 ✓
- 120 g butter
- 150 g ground almonds
- 170 g xylitol
Instructions 0 / 2
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1
Mix the crumble.
Cut the butter into pieces, add to the mixing bowl with the remaining ingredients and knead for 8 sec / speed 6.
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2
Use the crumble.
Use the low carb crumble topping as desired.
Tip: You can halve or double the quantities depending on how much you need.
Video
Nutrition per serving
Why ground almonds can replace flour
Classic crumble topping relies on two components: flour as the base and sugar as the crumb stabiliser. We need to replace both in the low carb version without losing what makes crumble topping what it is.
Ground almonds provide the base. Finer than coarsely ground nuts, they bind the butter in a similar way to flour and give the crumbs their typical crumbly texture. If you want an especially fine result, you can take whole almonds and chop them yourself at 5 sec / speed 8. With ready-ground almonds from a packet, we skip that step and add them straight to the mixing bowl with the butter and sweetener.
A note on almond flour: defatted almond flour is not the same as ground almonds. Almond flour has had the fat removed, so it lacks what absorbs the butter. The crumble turns dry and crumbly rather than buttery. We stick with regular ground almonds with their full fat content.
Xylitol versus erythritol: which works better in the Thermomix®
In the original recipe we use 170 g xylitol. Xylitol has two properties that make it ideal for crumble topping. The crystal size is very close to that of fine caster sugar, and the sweetness level is roughly equal to regular sugar. The crumble tastes just as sweet even though we have left out the sugar.
If you want to switch to erythritol, perhaps because xylitol is toxic to dogs in the household, there are two things to know. Erythritol has only about 70 percent of the sweetness of sugar, so it is better to use a blend of erythritol and a little stevia, or a ready-made erythritol-stevia mix. Also, erythritol has coarser crystals that leave a slightly cooling sensation on the tongue after baking. You either like that or you do not.
In both cases, the key point is this: the sweetener must not melt in the mixing bowl. The moment we choose too high a speed or knead for too long, the mixture heats up through friction and the xylitol starts to dissolve. The almonds then combine with the butter to form a paste and the crumble is gone. That is why we stick strictly to 8 sec / speed 6 and stop immediately.
Why the butter must be ice-cold
This is where most low carb crumble attempts fail. Butter at room temperature is soft enough to distribute evenly through the almond and xylitol mixture during kneading. That is exactly what we do not want. Crumble needs individual pieces of fat that stick together with the almonds and xylitol to form rough crumbs.
We take the butter straight from the fridge and cut it into pieces roughly the size of a fingernail. If you want to be really precise, pop the pieces into the freezer for 10 minutes before they go into the mixing bowl. That way the butter stays firm during kneading, breaks into small chunks, and draws the almonds and xylitol around them into crumbs.
A rule of thumb from our experience: if the butter leaves marks on the board when you cut it, it is already too warm. In that case, put it back in the freezer for 15 minutes before you start.
The right speed and time in the mixing bowl
The original recipe calls for 8 sec / speed 6. That is the safest approach. Speed 6 is high enough to break up the butter and combine it with the almonds, but not so high that everything turns to mush. 8 seconds is enough to create the crumb structure without the mixture warming up through friction.
If you have a TM31, you can also use the kneading mode for 30 seconds. The kneading mode works more gently and evenly, which can help with cold butter. On the TM5 and TM6, 8 sec / speed 6 is generally sufficient.
If large chunks of butter are still visible after 8 seconds, use the spatula to fold the mixture once and then give it another 3 to 4 seconds at speed 6. Never knead for a longer stretch in one go. That is the main mistake we made ourselves in the early days.
When the crumble turns into a solid mass
It happens. Usually it comes down to one of the three causes above: butter too warm, kneaded too long, or speed too high. You do not have to throw the mixture away though. Three options for rescuing it:
Option one: 30 minutes in the fridge. The butter firms up again, and the mass can then be roughly crumbled by hand and scattered over the cake. Works well, though the crumbs end up slightly larger than with the direct method.
Option two: use it as shortcrust pastry. Take the mixture out of the mixing bowl, press it together briefly with your hands, wrap in cling film and chill for 30 minutes. This becomes a low carb shortcrust pastry you can roll out for tartlet cases or biscuit bases. We have rescued more than one failed crumble attempt this way and turned it into a tartlet base.
Option three: add 10 g more almonds. If the mixture is only slightly too pasty, a small additional amount of ground almonds often does the trick. They absorb the excess fat and restore the crumbly consistency. No more than 20 g extra, otherwise the crumble turns dry.
What we use the crumble topping with
We use this crumble mainly as a topping for berry cakes, apple crumble and quark bakes. The 120 g butter and 150 g almonds are enough for a standard baking tray of about 30 by 20 centimetres. For a large 26 cm springform tin, we scatter the crumbs a little more densely and the quantity works just as well.
If you love classic crumble cake with a yeast dough, we also have a Streuselkuchen recipe in the Thermomix® with flour and sugar, as well as the standard crumble version with caster sugar. For our almond base, it is worth looking at the guide on how to grind almonds in the Thermomix®. If you use the crumble mixture as a shortcrust pastry base, our shortcrust pastry basic recipe is a good reference for the next steps.
Baking temperature and time
Low carb crumble topping made with almonds browns faster than classic flour-and-sugar crumble. Almond fat colours earlier than starch, which is chemistry, not a mistake. We usually bake it at 160°C top and bottom heat for 20 to 25 minutes, depending on the filling underneath.
With a fan oven, reduce the temperature by 10 degrees, so 150°C. As soon as the crumble is golden brown, take it out of the oven. If it gets too dark, it will taste bitter, because the sweetener caramelises differently from sugar and the almonds toast quickly.
How long the unbaked crumble keeps
Freshly made crumble keeps in an airtight container in the fridge for about 3 days. We often make double the quantity and freeze half. In a freezer bag it keeps for 3 months and can be scattered straight from the freezer onto the cake and baked without thawing. The baking time increases by about 5 minutes.
Goes well with: Apple cake.
Leftover baked crumble from the cake keeps airtight for 2 days. After that it softens and loses its crumbly texture. Warming it back up in the oven at 160°C for 5 minutes makes it crisp again.
More low carb inspiration and ideas to go with the crumble topping:
- Streuselkuchen in the Thermomix®
- Classic crumble topping in the Thermomix®
- Shortcrust pastry basic recipe in the Thermomix®
- Grinding almonds in the Thermomix®
