Japanese New Year Datemaki
1. Place first seven ingredients in a blender / mixer and process until smooth.
2. Add carrot, mushroom and mitsuba and gently mix them with a spoon.
3. Heat cooking oil in a tamagoyaki nabe (rectangular omelet pan), pour the mixture in the pan, cover, and cook over low heat for 10 minutes. Check if the bottom is brown or not. If the pan is too hot, cool the pan on a wet towel to prevent burning. After the bottom sets, flip over and cook the other side.
4. Cover the bamboo sushi-roll mat with plastic wrap.
5. Flip the omelet onto the mat. While it is hot, score with a sharp knife to prevent breaking, roll the omelet, fasten with rubber bands and allow it to cool until it sets.
6. Cut it into thick slices and serve warm or cold.