I've been meaning to post this for a while but the last couple of months before I left Japan the Bio Ojiyan Cafe became one of my favorite cafes.
Someone can correct me if I'm wrong but Ojiyan is actually the name of a dish that I believe consists of taking rice and cooking it with an egg and some soup stalk. What you get out if it is like a thick egg−rice soup. I'm guessing it's common to put toppings on that. The bio ojiyan cafe offers bbq pork + onions, raw tuna + kimchi, fried chicken, tuna salad among other things as toppings.
They also include some extras like a soft boiled egg, some toast and a small weiner cut to look like an octopus. That's a common thing for moms to do for their kid's lunch.
It is one of those things that even though I had never had it before came across as totally delicious comfort food.
They have other stuff on their menu as well if ojiyan doesn't sound like your thing. They also have setup a table with breads and pastries on it. I didn't quite get the relationship between the cafe and the bread. Whether they were just putting the products of another company on the table or whether they were making those bread items there and just selling them with a different brand name.
In any case their bread logo is hella cute
The Bio Ojiyan Cafe is in Harajuku at the end of Harajuku street. That in itself is just a fun and interesting area that I was always happy to be in. Directions and a map can be found here