HI,
I went to Mitsuwa yesterday to get ramen noodles. When I saw the Gabutto Burger stand, I beelined to order their Gabutto burger with egg. I was quite interested in their flavored fries until I learned the flavors were powders the customer shook onto their fries. I never found it a satisfactory experience at movie theaters, I didn't see it improving any fry.
When I asked the young man from the counter about the various burger selections, there were more omissions than useful information. He failed to mention the pork-beef combination, which I think is a critical element for a new customer. I finally read the descriptions to learn what I needed.
Upon receiving my burger and opening it, I found myself laughing at the bun's branding. It reminded me of old Bonanza show opening.

The dressing of the hamburger is a bit messy and slippery. There is the Kewpie mayo on the top bun, followed by lettuce, tomato and egg. The burger itself is drenched in the special Gabutto sauce.

The organic egg for the burger is poached.

When I very lightly patted the burger together, the egg yolk popped sending a river of yolk to mix into the already slippery sauce mix of mayo and Gabutto sauce.

As Pucca commented, this is a rather small burger though the patty is thicker than we experience at fastfood places. I was still hungry after eating it, then went for the soup noodles as originally planned.
Regards,