Melt the butter in a small saucepan over a medium heat and cook the shallots until soft. Pour in the wine and reduce by half. Add the mustard, saffron, cream and seasoning. Bring to the boil, remove from heat, stir in the chopped tomato and chives and keep warm. Heat a frying pan until hot, add the oil and cook the salmon fillets for 4-5 minutes each side until golden brown and slightly crispy. Cook the tagliatelle according to the instructions on the packet. Drain thoroughly. To serve drizzle the sauce over the pasta and top with the salmon. Garnish each one with two, long fresh chives. NOTES : The Tartan Quality Mark is the hallmark of premium quality Scottish salmon. Each fish has been produced to strict guidelines set down by an independently controlled, product certification scheme and has a unique identification number which allows it to be traced back to the farm. Fresh salmon takes only minutes to cook and is always special served simply with a freshly made sauce. An alternative serving suggestion would be to wrap the salmon in filo pastry, bake in the oven and serve with the saffron sauce.