Preheat your oven to 400°F and line a large sheet pan with parchment paper for easy cleanup.
Quarter the baby potatoes and halve the Brussels sprouts, then place them on the sheet pan.
Drizzle the vegetables with the olive oil and season with half of the salt, pepper, and dried oregano.
Toss the vegetables to coat evenly and spread them out in a single layer.
Roast the vegetables in the preheated oven for 15 minutes until they begin to soften.
Remove the pan from the oven, push the vegetables to the sides, and place the salmon fillet in the center.
Season the salmon with the remaining salt, pepper, oregano, and the minced garlic.
Return the pan to the oven and roast for an additional 10 to 12 minutes until the salmon is flaky and the potatoes are golden.
Squeeze the fresh lemon over the salmon and vegetables just before serving for a bright finish.