Chop leeks into medium size pieces and soak in cold water to eliminate dirt. Drain them. Melt 4 tbs butter on medium heat and saute leeks for 2 or 3 minutes. When soft and transparent, add 1 cup light cream, salt and pepper, and reduce until thickened. Set aside.
Chop shallots and saute them with 1 tsp butter. De glaze with white wine and reduce to dry. Add vegetable bouillon, saffron and reduce by half.
Incorporate the remaining butter slowly, mixing with a whisk until sauce thickens. Blend on high speed for 30 seconds. Set aside.
Saute the salmon, skin side down, on medium heat. When the skin is crisp, remove from heat and place in preheated oven (400 degrees) for 5 minutes. Remove from oven and allow to rest. Reheat leeks and the sauce and place 2 tbs of leeks in center of warm plate. Place salmon on top of leeks, skin side up, and pour sauce around.