Brine salmon in 4 tablespoons salt and 4 cups water for about 30 minutes. Heat broiler and grease baking sheet. In a small bowl, mix together mustard, garlic, shallot, thyme, rosemary, and lemon juice and season with salt and pepper. Rinse bring off salmon. Spread mixture all over salmon fillets and broil, 7 to 8 minutes.
Garnish with more thyme and lemon slices and serve.
