Spaghetti With Salmon Two Ways

To dress pasta? Olive oil, of course. But that was until I tried a generously buttered spaghetti at Arakataka restaurant in Oslo. Only after I unwound the disarmingly simple knot of fresh pasta strands tossed with butter and crowned with fish roe did the sumptuous complexity of flavors start to bloom. This was a dish I knew I would try to replicate at home. The challenge was the roe. The restaurant used lojrom, also called bleak roe, a fairly fine-grained roe that is popular in Scandinavia but hard to find in the United States. Other roes, like golden whitefish, trout and salmon, may be substituted. For a somewhat more substantial preparation, I added some hot-smoked salmon, ripe tomato and a hint of lemon.