First, heat 1 tbsp Japanese soy sauce (koikuchi shoyu), 1 tbsp mirin and 1 tsp sugar together in a small saucepan. Allow to boil for 30 seconds and then remove from the heat.
Transfer the mixture to heatproof jug or bowl.
Slowly pour in the ½ tbsp toasted sesame oil and ½ tbsp olive oil while whisking vigorously. Once emulsified, add ½ tbsp toasted white sesame seeds, ½ tsp garlic paste, ½ tsp lemon juice and 1 pinch ground white pepper. Mix and store in the fridge until use.
Place 30 g baby leaf spinach and 150 g mixed leaf lettuce in a bowl. Cube 1 avocado and half 100 g mini tomatoes, then scatter them around the bowl.
Arrange 200 g sashimi-grade fish on the top. Whisk or shake the dressing before pouring. Pour the dressing over the salad right before serving, mix well and enjoy!
Notes
Store dressing in a sealed container in the refrigerator for up to 1 week.