Preheat oven to 425°F. Line a baking sheet with parchment paper.
In a skillet over medium heat, melt butter. Add breadcrumbs, garlic powder, and ¼ teaspoon salt, stirring often until golden brown, about 3 to 4 minutes. Remove from heat.
Pat halibut fillets dry and place them on prepared baking sheet. Season each filet with salt and pepper on each side. Spread Dijon mustard evenly over the top of each fillet.
Press the toasted breadcrumb mixture onto the mustard-coated surface.
Bake for 18 to 20 minutes, depending on the thickness of the fish, until the fish is opaque and flakes easily with a fork.
Serve immediately and enjoy!
