Slice the potatoes into 1-1.5cm thickness and soak them in cold water for 20 minutes to remove starch.

Cut the beef into bite-sized pieces and marinate with 1 tbsp sake and a pinch of pepper.

In a pan, stir-fry the beef until the surface is slightly cooked, then add the potatoes and stir-fry together.

Add 1 mug of water and 3 tbsp soy sauce to the pan. Cook on high heat until boiling, then reduce to medium heat and add 2 tbsp oligosaccharide syrup. Simmer until the potatoes are tender.