Heat a large cast iron skillet over medium-high heat.
When the skillet is hot add butter and olive oil. Heat until the oil is hot and butter is bubbling.
Add the salmon filets, skin-side down. Using a fish spatula, gently press down on the filets to ensure skin has full contact with the pan.
Turn the heat down to medium and cook the salmon for 3 or 4 minutes. Gently turn the salmon over and cook for 1 or 2 more minutes. Remove from the skillet and set aside.
To the same pan, add the chopped shallot and cook for 2-3 minutes over low heat, then add minced garlic and thyme leaves, sauté for 30 seconds until garlic is fragrant.
Deglaze the pan with the white wine and let it simmer for 5 minutes until the liquid reduces by half.
Still on low heat, add in Organicville Salt Free Stone Ground Mustard, chicken stock and the heavy cream, stir and let it simmer for 5 minutes longer.
Bring the salmon back to the pan and let it simmer in the sauce for 5-7 minutes until the salmon is opaque and cooked all the way through and the sauce is desired consistency.
Taste the sauce and add more salt and pepper if necessary.