In a large skillet, heat 1 one tablespoon each of olive oil and butter. Add the mushrooms and sauté until soft, about 5-6 minutes, stirring occasionally. Feel free to add in some wine if the pan is getting dry. When almost cooked, toss in the fresh herbs. Remove from pan and set aside. Season salmon fillets with salt and pepper, then spread about one teaspoon of truffle mustard onto each fillet. Add remaining olive oil and butter to the pan. Once hot, place salmon fillets, top side down. Sear for about 3-4 minutes without moving, then flip over and cook for an additional 2-3 minutes for medium rare. Meanwhile, whisk together mustard, sour cream, honey and 1/2 teaspoon each of salt and pepper. Serve salmon over mushrooms and, if you like, jasmine rice. Top with a dollop of the truffle cream. I added some chopped bell peppers for added color and texture.