Sous-Vide Mashed Potatoes

Ingredients
1kg Russet (kruimig/bloemig) potatoes
5 cloves of garlic
225gr unsalted butter
235ml milk
3 sprigs of rosemary, plus more for serving
Seasalt and white pepper
Method
Set the Anova Sous Vide Precision Cooker to 90ºC.
Rinse and peel the potatoes. Slice into 3mm-thick rounds.
Smash and peel the garlic cloves.
Combine the potatoes, garlic, butter, milk, rosemary, and 2 teaspoons salt in a large zipper lock or vacuum seal bag. Seal the bag using the water immersion technique or a vacuum sealer on the moist setting. Place in the water bath and set the timer for 1 1/2 hours.
When the timer goes off, remove the bag from the water bath. Pour the entire contents of the bag through a strainer set in a medium bowl. Discard the rosemary.
Transfer the potatoes to a large bowl and mash using a potato masher, rice, or food mill. To get a super smooth texture, pass the mashed potatoes through a tamis, chinois, or sieve. (Do NOT use a food processor, electric mixer, or blender – due to the starch in the potatoes, if you over mix the potatoes you’ll end up with a gluey texture.)
Gently stir the strained melted butter and milk into the mashed potatoes. Season to taste with salt and white pepper. Garnish with additional fresh rosemary. Serve.
Notes
Source