Boil the rice for 10 to 12 minutes. Drain and add butter.
Cook the eggs hard-boiled, then chill, peel, and chop.
Sear the mushrooms in a pan.
Poach the salmon fillet (cover with cold water and a glass of white wine, simmer for 3 minutes). Chill in the broth.
In a springform pan, layer half of the rice, the eggs, the fish, the herbs, the mushrooms, and the other half of the rice. Press into the mold and refrigerate.