To start the sauce In a shallow saucepan, combine the cr?me fra?che, saffron, half stock cube and tomato ketchup. Reduce to half the original quantity over a medium heat. Season with salt and a pinch of crushed dried chillies. Keep warm. To prepare the salmon fillets Brush a large shallow non-stick saute pan with a little olive oil, or butter. When hot, place the salmon fillets in the pan. Top each fillet with a sprig of fresh rosemary. Pour over champagne. Cover pan and steam salmon fillets for 5 minutes or until the fish is steamed to a pale pink on the outside, but still coral pink and moist on the insides. Increase heat under the pan, crumble in vegetable stock cube, and with a spatula, transfer the salmon fillers to heated dishes. Remove sprigs of rosemary and garnish with fresh green sprigs (which you have steeped in a little boiling water). Stir some of the pan juices into the reduced sauce and strain around salmon fillets.