Preheat the oven to 425 degrees.
Line a rimmed baking sheet with parchment paper. Lay 3 lemon slices in a single row for each piece of salmon.
Place each piece of salmon on top of the lemon bed. Check for fish bones. Remove the fish bones with fish tweezers if needed.
Spread or brush the top of the filets with dijon mustard.
In a bowl, stir together the brown sugar topping ingredients.
Sprinkle the brown sugar topping on top of the mustard salmon. Make sure to cover the salmon all over.
In a small bowl, combine the panko parsley ingredients.
Sprinkle on the panko topping on the salmon. It's okay if some falls off.
Bake for 15-18 minutes, or until the salmon is no longer opaque in the middle.