1. Dice scallion; shred red chilli pepper; juice and drain lime and lemon, set aside.
2. Mix sake, mirin, soy sauce, lime and lemon juice to make citrus dressing. Pour into a saucepan, add dried bonito flakes and boil for 1-2 minutes to evaporate the alcohol, drain and discard the bonito flakes, set aside.
3. Add a little salt and pepper on both sides of sirloin steak, pan fry each side for around 2 minutes until cooked medium, set aside to cool for a while, then cut into thick slices.
4. Add oil to a heated oil, sauté shimeji mushroom, season with salt, black pepper and sake, stir fry until brown, set aside.
5. Cool ingredients, then start plating: first put shimeji mushroom at the bottom, then place the steak over, scatter diced scallion, red chilli pepper shreds, deep fried shallot or garlic, drizzle citrus dressing and serve.