Pat the surface of 2 salmon fillets dry with kitchen paper. Rub ½ tsp salt on both sides and rest for 10 minutes. While you wait, start boiling a pot of water.
After 5 minutes, the salt will have drawn out the excess moisture, so pat dry once more.
Once the water is boiling, turn the heat down to a simmer and add the salmon. Simmer for 5 minutes.
Take the salmon out of the pan and gently shake off the excess water. Transfer it to a container and carefully pull off the skin (you can fry this and eat it as a snack, or discard). Use a spatula to break it up and remove any bones with tweezers.
Heat a frying pan on low to medium-low and add 1 tsp butter. Once melted, add the salmon flakes along with ½ tbsp sake, ½ tbsp mirin and ⅛ tsp salt. Mix well and continue to heat until the liquid has almost gone.
Turn off the heat, and mix in ¼ tsp Japanese soy sauce (koikuchi shoyu) and 1 tsp toasted white sesame seeds.
Use straight away or transfer to a clean container and leave to cool. Once cool to the touch, cover and store in the fridge for up to 5 days.
Enjoy with rice!
Notes
Look for visual cues when cooking - stop when salmon looks fluffy with small air pockets while still slightly moist, not completely dry.
Store in clean containers and always use fresh utensils when serving.
Store cooled salmon flakes in airtight containers for up to 5 days in the refrigerator or freeze in individual portions for up to 1 month.