This may not look like something you see in an Izakaya, but any good hearty breakfast item, in our opinion, can be had as a “shime” 締め or a mid-night snack after drinking–for those who are young and reckless. Stuffed omelets are very popular in Japan including ones stuffed with rice seasoned with ketchup called “Omuraisu” オムライス.
We are not big omelet eaters anymore but, in our reckless days, we often looked for nice brunch/omelet places over the weekend. While we were living in Los(t) Angles, our friend introduced us to one such place near the famous La Brea tar pit. We cannot remember the name of the place and I am sure it does not exist any longer. After that, I emulated how they made omelets at home. Omelets were cooked to order in front of the customers. There were many kinds of fillings to choose from, which were kept in a warming drawer.
Filling: I use whatever is available at the moment. This time, for one two-egg omelet, I use red onion (thinly sliced, 1/3 medium), fresh shiitake mushroom (stem removed and sliced, 4-5 medium), leftover oven roasted pork fillet (4-5 thin slices cut into strips), baby spinach (a very small handful) and fresh goat cheese (3 tbs). I first saute the onion in the mixture of olive oil and butter, add the pork and shiitake mushroom. After they are cooked, I add spinach and saute until wilted. Season with salt and pepper. Since nice “fond” is formed, I deglaze it with a Marsala wine (1 tbs, optional) and cook it until liquid is all gone. I add crumbled goat cheese (I do not mix at this point) and leave the mixture on the stove on a very low flame (our stove has a very low simmer setting or use as a “warm” setting if you are using an electric stove top) (#1, image below).
This is very satisfying dish. Since I am not making a living doing this, it is kind of fun to make omelets every-now-and-then. I had to admit that we had this as a breakfast not as a mid-night snack and we share one omelet.