Melt the butter in a large frying pan over a low heat. Add the oil and shallots and cook, stirring occasionally, for 6–7 minutes until softened. Pour in the wine, increase the heat to high and boil rapidly for 2–3 minutes until reduced by half. Remove from the heat and stir in the crème fraîche and salmon strips. Season with salt and plenty of pepper.
Cook the pasta in a large saucepan of salted boiling water according to the packet instructions until al dente. Drain, reserving a ladleful of the cooking water.
Bring the pasta sauce to a slow simmer, then add the pasta and stir until well combined. Add the reserved cooking water from the pasta and continue stirring until the pasta is well coated and looks silky. Gently toss in the dill and roe, and serve immediately.