Dashi maki tamago (omelet)

4 eggs
90 ml dashi
2 ΒΌ white sugar
1 Tbsp sake
1 Tbsp mirin
Pinch salt
Cooking oil
Heat the stock, sugar, sake, mirin and salt in a pot, stirring until the sugar is dissolved.
Let cool. Beat the eggs well and stir in the stock mixture. Heat oil in a non
stick-frying pan. Over medium heat, pour in a quarter of the egg mixture. When the
surface begins to dry, fold it in thirds. Push the folded egg to one end of the pan.
Pour another fourth of the egg mixture all around the pan, underneath the cooked egg as
well, and fold in thirds again when ready. Repeat until all the egg is cooked. Shape
the egg using the corners of the pan.