You may be wondering what a potato foam is and how it’s different from plain mashed potatoes. For one, it’s certainly not plain. Enriched with a musky truffle aroma, it’s a truffle lover’s delight. Besides that, the rich yet lightweight mouthfeel makes it the perfect side dish for a decadent dish like this tangy, cured mackerel. Served in a crispy potato tube, this potato foam takes a chic spin on the classic mashed potato.
Potato Foam Ingredients
- 300 g overcooked potato
- 250 g truffle-infused whole milk
- 10 g truffle oil
- 5 g potato protein
- 1 g xanthan gum
- 3 g sodium alginate
Potato Tubes Ingredients
- 300 g overcooked potatoes
- 700 g potato cooking water
- 100 g isomalt
- 9 g konjac (such as from Sosa)
Cured Mackerel Ingredients (single serving)
- 200 g fresh mackerel
- 50 g table salt
- 50 g castor sugar
- 10 g orange zest
- 2 g coriander seeds, toasted and crushed
- 100 g whole sheep milk
- 3 g white truffle, chopped
- 20 g coriander oil
To ensure a smooth cooking experience, please read the Smartwhip care and safety guidelines before usage.
- Prepare the cured mackerel by washing, trimming and fileting the mackerel as you would serve it. Mix the salt, sugar, orange zest and toasted coriander seeds in a bowl, then massage the paste into the mackerel filet, ensuring the meat is fully coated. Place the mackerel in the fridge to cure for approximately 1 hour, then wash it with cold water and portion it.
Prepare the potato tubes by preheating the oven to 160ºC. Blend the overcooked potatoes, cooking water, isomalt and konjac together at high speed until the ingredients are fully homogenised, then spread the mixture out evenly on a lined baking tray.
Tip: Use cooking spray to ensure the potato tubes don’t stick to the baking sheet.
- Bake the potato tube mixture at 160ºC for 9 minutes, then take the tray out of the oven and cut evenly sized squares of about 6 cm to make the potato tubes. Reduce the oven temperature to 130ºC, then roll the potato tubes up, as seen in the image above. Place the potato tubes back into the oven at 130ºC for 6 minutes, then allow them to cool in a very dry place.
- Prepare the potato foam by blending the overcooked potatoes, truffle-infused milk, truffle oil, potato protein, xanthan gum and sodium alginate until you achieve a smooth consistency. Sieve the potato foam mixture into a siphon, then connect your Smartwhip cream charger and charge it to 8 bar. Disconnect your siphon and shake it for 5-10 seconds to evenly distribute the gas. Place the potato foam in the sous vide machine at 65ºC for at least 30 minutes before serving.
- For the optional sauce, pour the sheep milk, coriander oil and white truffle into a vacuum bag, then slow cook it in the sous vide machine 55ºC for 4 hours.
Place the cured mackerel in the centre of the plate and surround it with 2-3 potato tubes. Fill each potato tube with potato foam, and garnish the dish with some blanched baby asparagus, shimeji mushrooms and the sauce.