Crack and beat the eggs, in a bowl with a spoon or a fork, until the yolks and whites are blended well with no visible strings of whites. Stir in a pinch of salt. (If using, stir in chopped vegetables.)
Add a teaspoon of vegetable oil to a medium size non-stick pan and distribute the oil evenly using a napkin or paper towel. Preheat over medium low heat, until it feels hot when you place your hand 2 to 3 inches above the bottom of the pan.
Add β of the eggs to the pan. Swirl it around to cover the pan. (Reduce the heat or raise the pan away from the heat, for a little while, if the egg is cooking too fast.) See note 2.
When the egg is set but the surface is still wet, add a sheet of gim. Pour the remaining egg over the gim and swirl the pan around to spread the egg mixture evenly.
When the egg surface is set again, using a spatula, lift one end of the egg (about 1-1/2 inch) and fold it over to the other side. Quickly lift the folded part and fold it again. (The egg should be slightly wet while being folded, or the roll will become loose when sliced.)
Repeat the process until an egg log is created.
Remove from the pan and let cool for about 5 minutes. Slice the egg into thick, even pieces (3/4 to 1-inch thick).
Notes
You can use 4 eggs with 1-1/2 sheets of gim to make a thicker roll, using the technique below.
If you want to try more layers, pour the egg mixture into the pan in 2 batches with 1-1/2 sheets of seaweed. First add β of the egg mix, use 1 sheet, spread some egg mix over the seaweed, roll, move it to one side. Pour the remaining egg on the other side, and add 1/2 sheet of gim. Watch the technique here.