Preheat oven to 400 degrees. Line baking sheet with foil. Whisk together brown sugar, soy sauce and Dijon mustard. Place fillets on baking sheet, season lightly with salt and pepper. Brush with glaze. Bake in oven for 6-8 minutes until salmon is flakey. Remove from oven and serve.
This can also be cooked on a grill. Place on aluminum foil and cook for 5 minutes or until salmon is flakey.