Rhubarb quark mug cakes made in the Thermomix® are our go-to spring dessert when rhubarb is in season. The combination of creamy quark filling, tangy rhubarb and buttery crumble works better in mugs than in a large tin, because each portion gets its own crispy crumble layer.
We have been baking these mug cakes every year between April and June. The trick is that the crumble serves two purposes. Half is pressed down as a base, forming a stable layer for the moist quark filling. The other half goes on top loosely and crisps up during baking. Without the firm base, the quark filling soaks into the mug and becomes soggy.
Rhubarb Quark Mug Cakes with the Thermomix®
Ingredients 0 / 10 ✓
- 100 g flour
- 60 g sugar
- 60 g butter cold, plus a little extra for greasing the mugs
- 1 tsp baking powder
- 1 egg
- 1 stalk rhubarb
- 300 g quark
- 50 g sugar
- 1 sachet vanilla sugar
- 1 tbsp cornflour
Instructions 0 / 7
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1
Preheat the oven.
Preheat the oven to 180 °C. Grease the mugs with butter.
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2
Whip the egg white.
Insert the butterfly whisk. Separate the egg and place the egg white into the mixing bowl. Whip for 1 min / speed 4 until stiff, then set aside. Remove the butterfly whisk.
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3
Mix the crumble.
Add the flour, sugar, butter and baking powder to the mixing bowl and mix for 30 sec / speed 4.
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4
Distribute the crumble.
Spread half the crumble into the mugs and press down lightly. Set the remaining crumble aside.
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5
Prepare the rhubarb.
Wash, peel and cut the rhubarb into small pieces. Add to the mixing bowl along with the egg yolk, quark, sugar, vanilla sugar and cornflour, then mix for 10 sec / reverse direction / speed 3.
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6
Fold in the egg white.
Gently fold the whipped egg white into the mixture using the spatula, then spoon the mixture into the mugs.
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7
Bake.
Scatter the remaining crumble over the top and bake on the middle shelf for 25 minutes.
Nutrition per serving
Why the egg white is whipped separately
The whipped egg white makes the quark filling light and airy. We whip the egg white with the butterfly whisk until stiff, before mixing the crumble. The egg yolk goes directly into the quark filling later. This order saves washing up: only the butterfly whisk needs a quick rinse after the egg white, and the mixing bowl stays clean for the crumble.
1 minute at speed 4 is enough for stiff peaks. Longer is unnecessary, but shorter and the egg white will not be firm enough and will collapse when folded in. The egg white must be completely free of yolk, otherwise it will not whip up properly.
Crumble technique: pressed and loose
The crumble comes together in 30 seconds at speed 4 from cold butter, flour, sugar and baking powder. Cold butter is important because warm butter turns the crumble into a dough. The mixture should be crumbly, not smooth.
Half the crumble is spread into the greased mugs as a base and pressed down with a spoon or finger. This forms a barrier between the mug and the quark filling. The other half is set aside loose and goes on top after the quark filling has been spooned in. These crumbs become crispy and golden during baking because they are exposed directly to the heat.
Preparing the rhubarb
Rhubarb needs to be peeled. The fibrous outer skin is tough and unpleasant in the quark filling. We cut the stalk into manageable pieces, slide a knife under the skin and pull the fibres downwards. This is easy with fresh rhubarb, but older stalks can be trickier to peel.
The peeled pieces go into the mixing bowl with the egg yolk, quark, sugar, vanilla sugar and cornflour. 10 seconds in reverse direction at speed 3 combines everything without reducing the rhubarb to a puree. The cornflour absorbs the moisture the rhubarb releases during baking. Without it, the filling becomes watery.
Folding in the egg white and filling the mugs
The whipped egg white is folded gently into the quark filling by hand using the spatula. Do not use the Thermomix® for this step, as that would cause the egg white to collapse. The mixture will be light and will rise slightly during baking.
Spoon the quark filling on top of the pressed crumble in the mugs, filling them about two thirds full. Scatter the remaining crumble on top without pressing it down. Bake for 25 minutes at 180 °C on the middle shelf, until the crumble is golden and the quark filling has set.
Serving
The mug cakes taste best served warm. Straight from the oven they are too hot and the quark filling has not yet fully set. After 10 minutes of cooling they can be turned out of the mugs or eaten directly with a spoon.
Goes well with: vanilla ice cream and yoghurt.
More rhubarb recipes: Rhubarb compote, Rhubarb jam, Cheesecake with rhubarb, Rhubarb vanilla liqueur.
