Sous-Vide Beef Cheeks, Mashed Potatoes and Spinach

Sous-Vide Beef Cheeks

• 25 oz beef cheeks cut into 4 slices (approx. 1 in. thick)
• 14 oz beer unfiltered
• 1 tsp salt
• 1 pinch ground black pepper
• 2 oz celery cut into pieces
• 1 ½ oz carrots cut into pieces
• 2 oz yellow onions halved
• water to fully submerge bags (not higher than the max. fill level)
• 1 oz lemon juice, freshly squeezed (approx. ½ lemon) (see Tip)
  或 1 tsp ascorbic acid (vitamin C powder)

Parmesan Mashed Potatoes

• 1 oz Parmesan cheese cut into pieces
• 1 garlic clove
• 2 oz extra virgin olive oil
• 5 ½ oz fresh spinach leaves squeezed to fit mixing bowl
• 35 oz russet potatoes peeled, cut into pieces (½ in.)
• 10 oz water plus 1 tbsp
• 1 tsp salt plus extra to season, to taste
• 1 tbsp corn starch
• 2 oz unsalted butter divided
• 1 tbsp Dijon mustard
• 2 - 3 pinches ground black pepper plus extra to season, to taste
• 1 - 2 pinches ground nutmeg