Roast Beef Nigiri

It's more or less impossible to find raw fish that's suitable for this around here, so I made landlocked nigiri sushi. Sometimes I've seen "sashimi grade tuna," but I'm not so sure I trust that.
My immature rice technique contributed to these beasties being quite delicate and difficult to eat, but they tasted very good. The flavors of roast beef and soy sauce combine beautifully - it's an umami smackdown. I think next time I'll have some nori on hand to tie a band around the nigiri to hold it together, like they do with unagi sushi:

Perhaps a small roll with roast beef and scallions inside would be good, and easier to eat. I love the combination of beef and scallions.