I found it!
I have managed to find two places in Sacramento that serve soon tubu chigae, or spicy soft tofu soup. Mmmm! Spicy and thick - they bring it boiling and bubbling to the table with a raw egg that you break, drop in and cook right there. A bowl of rice accompanies the soup to help quench the heat from the peppers in the soup.
A-Rang (9679 Folsom Blvd) is my favorite restaurant for this dish. It's a very small space in a strip mall at Folsom and Bradshaw. The waitress/hostess/busperson was very friendly and introduced herself at the end of the meal as Ji.
Last time I was there I had the kimchee chigae which was flavorful, with lots of chunks of kimchee, tofu and beef. It was quite spicy - runny nose and the whole bit - but not so much that it overwhelmed the full-bodied flavor of the broth. Ji later told me that she put one less pepper than usual so it was a little less spicy than the regular version - I thanked her profusely!
My boyfriend had the dolsit bi bim bap which is bi bim bap served in a hot stone bowl. (Bi bim bap is a variety of fresh and preserved thinly chopped vegetables, barbecued beef and a touch of Korean spicy sauce, served with hot rice and a fried egg) The rice gets all brown and crispy from heat of the stone bowl, which adds a smoky flavor and cruncy texture. Unfortunately the vegetables end up less crunchy since they also get cooked slightly - it's a trade-off.
Overall, very tasty. A place I'll definitely return to.
The other place that I found this spicy tofu soup is the Korea House just down Folsom on the other side of Bradshaw. They serve Korean barbecue, which is extremely unusual in Sacramento so it might seem to be a waste to go there and order the chigae. The soon tubu chigae was quite tasty there too. I've rambled on for too long now. Gotta go make supper!