In a pan, heat oil on medium then add the beef; breaking it up as you cook. When it's almost browned, add sugar, distributing it evenly.
Add sliced onion and fry. Add the soy sauce and sake. Cook covered on medium-low heat until the onions are translucent.
Reduce the liquid to your desired thickness, I like mine a little soupy. Leave uncovered until it's cooked to your liking.
Serve in a bowl topped with a soft boiled egg (optional). The picture shows just the yolk arranged on top.
If you'd like, garnish with a couple pieces of diagonally cut leeks.
Story Behind this Recipe
I wanted to make a beef bowl, the same way I made sukiyaki.
Since this recipe uses a lot of onions you may want to add more soy sauce. This is my mom's way of making sukiyaki. Kansai-style doesn't use wari-shita (stock used to flavor sukiyaki), so it's a little strong and perfect over rice.