Combine Dijon, mustard powder, sugar and vinegar. Pour in oil slowly while mixing to combine well. Add dill and check seasoning. Store sauce chilled until ready to use.
Lightly oil a baking sheet. Place thawed salmon, skin side down, on baking sheet.
Sprinkle salmon portions with salt and pepper. Brush with a thin coating of sauce.
Bake for about 12-15 minutes, or until cooked through. Top with remaining sauce and serve.
Excellent served with boiled small new potatoes and steamed green beans.