Sous-vide Cantonese-style Beef, Tomato and Onion Stir Fry

Sous-vide Beef

• 2 beef flank steaks (approx. 400 g each, see tip)
• 30 g fresh root ginger, peeled, cut in round slices (2 mm)
• 3 garlic cloves
• 40 g dark soy sauce
• 50 g light soy sauce
• 30 g toasted sesame oil
• 1 Tbsp oyster sauce
• 2 tsp brown sugar
• 2 - 3 pinches ground cloves, to taste (optional)
• 2 star anise
• 1400 g water (approx. or enough to fully submerge bags but not higher than the maximum capacity of the bowl)
• 30 g lemon juice, freshly squeezed (see tip)
  or 1 tsp ascorbic acid powder
• water, cold, for cooling

Stir-fry Vegetables and Assembly

• 50 g water, plus 1½ Tbsp for mixing with cornflour
• 2 Tbsp rice wine (see tip)
• 2 Tbsp rice vinegar
• 1 Tbsp cornflour
• 3 Tbsp oil
• 100 g onions, halved then sliced in half-moon rings
• 150 g tomatoes, cored, quartered
• 150 g peppers, red or yellow, cut in pieces (2 cm)
• 1 spring onion, thinly sliced (approx. 2 mm), for garnishing
• sesame seeds, for garnishing
• jasmine rice, for serving (see tip)