Step 4: Fini!
That's it. Refrigerate until needed, but remember that with a large butter content you'll want it to warm somewhat before serving or it won't be very spreadable. If you want to be fancy, you can use an icing bag to squirt the spread into an aesthetically pleasing shape, but that won't change the taste.
Serve alongside appropriate breads, toast pieces, crackers, etc, and of course the smoked salmon. (here, we see some smoked sockeye Salmon on slices of French roll.)