Cooking sweet potatoes in the Thermomix® works best in the Varoma®. The quick guide for 800 g: cut into 2 to 3 cm cubes, add 1,000 g of water or vegetable stock plus 1 tsp of salt to the mixing bowl, spread the sweet potatoes across the Varoma tray and the steaming tray insert, and cook for 25 to 30 minutes at Varoma® / speed 1. Whole sweet potatoes up to 300 g need 60 to 70 minutes. This works identically on the TM31, TM5, TM6 and TM7.
We almost always cook sweet potatoes in the Varoma® rather than directly in the mixing bowl, and there is a solid reason for it. When boiled in water, the cubes absorb liquid and turn watery and bland, whereas steaming keeps the flavour and vitamins locked inside the flesh. While the sweet potatoes steam above, the mixing bowl below stays free for a sauce, a curry, or a puree. That parallel use is exactly where the Thermomix® pays for itself here.
Steamed Sweet Potatoes in the Thermomix® Varoma®
Ingredients 0 / 2 ✓
- 800 g sweet potato
- 1000 g vegetable stock
Instructions 0 / 3
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1
Prepare the sweet potatoes.
Wash the sweet potatoes, peel if needed and cut into your preferred shape.
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2
Add the vegetable stock.
Pour the vegetable stock into the mixing bowl.
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3
Cook the sweet potatoes.
Spread the sweet potatoes across the Varoma tray and the Varoma steaming tray insert. Place the Varoma in position and cook for 45 minutes / Varoma / speed 1.
Tip: If you cut the sweet potatoes into thin slices, the cooking time will be shorter.
Video
Nutrition per serving
Cubed or whole: how to control the cooking time
The cooking time depends almost entirely on how you cut the sweet potato, not on the variety. Even 2 to 3 cm cubes are butter-soft after 25 to 30 minutes at Varoma® / speed 1. Thin slices of around 1 cm are done in just 18 to 20 minutes, while whole sweet potatoes up to 300 g need 60 to 70 minutes. The key is to keep all the pieces a similar size, otherwise the small ones fall apart while the larger ones stay firm inside.
We always add 1,000 g of liquid to the mixing bowl, because with a 45-minute cooking time for the full 800 g portion the steam needs to keep going without needing a top-up. With less than 500 g of water the bowl runs dry towards the end and the sweet potatoes are only half cooked. A single layer in the Varoma tray plus a single layer on the steaming tray insert cooks more evenly than a high pile on one level.
Peel or leave the skin on: what works when
With organic sweet potatoes we leave the skin on. Most of the fibre sits just beneath it, and after steaming the skin is so soft that it can be eaten as it is or slipped off with a spoon. For a smooth puree we peel beforehand, because skin fibres disrupt the creamy texture. Always scrub thoroughly with a vegetable brush before cutting, as sweet potatoes often carry soil.
Water or vegetable stock in the mixing bowl is a matter of taste. Stock seasons the flesh from within, because the condensation during steaming draws lightly into the cubes. For a savoury side dish we use stock; for sweet variations or baby food we use plain water. If you like a little extra depth, add a crushed garlic clove and a bay leaf to the cooking liquid.
Common pitfalls when cooking sweet potatoes and how we avoid them
The puree turns gluey and sticky instead of creamy
Sweet potatoes contain a lot of starch. Blending them for too long or at too high a speed breaks down the starch and the puree becomes gummy like paste. Our solution: blend the cooked sweet potatoes for only 20 to 30 seconds at speed 4, remove the butterfly whisk first, and work with 30 g of butter and 50 ml of warm milk. Not at speed 8 or above, as that makes any starchy vegetable tough.
The cubes are soft on the outside but still hard inside
This happens with pieces that are too large or uneven, and when the Varoma® is not seated properly. Our solution: aim for even 2 to 3 cm cubes, click the Varoma® firmly into place until you hear it lock, and halfway through give the top and bottom layers a gentle toss. A dense pile blocks the steam; a flat, spread-out arrangement cooks evenly all the way through.
The sweet potato tastes watery and bland
This is the classic problem with boiling in water, not with steaming. Our solution: always cook in the Varoma® rather than boiling in the mixing bowl. That way no water enters the flesh and the natural sweetness is preserved. If you want even more depth, roast the finished cubes in the oven at 220 degrees C for 10 to 15 minutes and the surface sugar will caramelise.
Four ways to use your cooked sweet potatoes
Creamy sweet potato puree: cook 800 g of peeled cubes, drain, then blend with 30 g of butter, 50 ml of warm milk and a pinch of nutmeg for 20 to 30 seconds at speed 4. We use the same gentle technique for our mashed potatoes with the Thermomix®.
Sweet potato chips: cut into 1 cm sticks, pre-cook in the Varoma® for just 18 to 20 minutes, then toss with 1 tbsp of olive oil and paprika and bake in the oven at 220 degrees C for 15 minutes until crisp. Pre-cooking then finishing in the oven gives chips that are creamy inside and firm outside without any deep-frying.
Spiced up: mix the finished cubes with half a chilli, a finely chopped garlic clove and a squeeze of lime. Goes well with bowls and grilled meat.
Baby food: cook in plain water, then blend smooth with a little of the cooking liquid. From six months onwards this is a great first food, because sweet potato is naturally mild and sweet. More ideas in our potato, vegetable and meat puree with the Thermomix®.
What goes with steamed sweet potatoes from the Thermomix®
As a side dish, sweet potatoes work with almost anything that is boldly seasoned. With lamb and game the puree provides a sweet contrast; in a bowl with quinoa, feta and pomegranate the cubes become the star of the dish. If you want to do everything in one go, steam some broccoli with the Thermomix® in the Varoma® at the same time and cook a sauce base in the mixing bowl below.
The cooked cubes also form the base for a sweet potato soup with the Thermomix® or a vegetable curry with chicken in just a few minutes. If you want to learn more about steaming in general, all the details are in our Varoma® guide.
How long cooked sweet potatoes keep
Cooked sweet potatoes keep in an airtight container in the fridge for 3 to 4 days. To reheat, we put them in a pan with a little butter so they go crispy on the outside like fried potatoes. Puree is best warmed back up to a creamy consistency with a splash of milk in a small saucepan.
Goes well with: salmon and sour cream.
Frozen, cooked cubes or finished puree keep for about 6 months. We freeze in individual portions in small containers or ice cube trays, which is handy as a puree stock or for baby food. Defrost overnight in the fridge and warm through briefly before serving. We do not freeze raw, cut sweet potatoes as they turn glassy when thawed.
