In a small mixing bowl, preferably one with a spout for easy pouring later, mix together eggs, dashi, salt and monkfruit erythritol sweetener until well combined.
Heat up tamagoyaki pan (or a normal round pan) over medium heat. Oil the pan lightly, using a small piece of paper towel to absorb excess oil. Keep the paper towel.
Pour 1/4 of the egg mixture into pan. If using seaweed, place a piece on top of the egg mixture now. When the bottom of the omelette is set but the top is still a bit runny, gently roll the egg to one side.
Lightly oil the pan again with the paper towel from before. Pour another 1/4 of the egg mixture into the pan. Lift up the rolled egg and let the new egg mixture flow underneath it. When the bottom is set but the top is still a bit runny, gently roll the egg to one side.
Repeat two more times with the remaining egg mixture, continuing to roll the egg into a large omelette roll.
Remove omelette from heat. Let cool slightly before cutting into bite-sized pieces. Enjoy!