Preheat your oven to 400°F. Line a baking sheet with parchment paper.
In a small bowl, mix together the Dijon mustard, olive oil, garlic powder, thyme, salt, and pepper.
Place the halved baby potatoes on one side of the prepared baking sheet. Drizzle with olive oil, season with salt and pepper, and toss to coat.
In a separate bowl, combine the panko breadcrumbs with melted butter and a pinch of salt. Mix until the breadcrumbs are evenly coated.
Place the salmon fillets on the other side of the baking sheet. Brush the Dijon mixture over the top of each fillet.
Press the panko mixture onto the top of the salmon fillets to create a crust.
Bake in the preheated oven for 20-25 minutes, or until the salmon is cooked through and flakes easily with a fork, and the potatoes are tender and golden brown.
Remove from the oven and sprinkle with fresh parsley before serving.