Preheat the oven to 425°F (220°C).
In a large bowl, toss the halved baby potatoes with 1 tablespoon olive oil, garlic powder, dried thyme, dried rosemary, salt, and black pepper until evenly coated.
Spread the potatoes in a single layer on a baking sheet lined with parchment paper or foil.
Roast the potatoes in the preheated oven for 20 minutes.
While the potatoes are roasting, pat the salmon fillets dry with paper towels and season both sides with salt and black pepper.
After the potatoes have roasted for 20 minutes, remove the baking sheet from the oven and push the potatoes to one side.
Drizzle the remaining 1 tablespoon olive oil over the empty side of the baking sheet.
Place the salmon fillets skin-side down on the oiled side of the baking sheet.
Arrange lemon slices on top of each salmon fillet.
Return the baking sheet to the oven and roast for an additional 10 minutes, or until the salmon is cooked through and flakes easily with a fork, and the potatoes are golden and crispy.
Remove from the oven and sprinkle chopped fresh parsley over the salmon and potatoes before serving.