Preheat the oven to 400 degrees F. Peel and dice the sweet potatoes and onion. Spread the salmon fillets, sweet potatoes, Brussels sprouts, and onion on a sheet pan.
Combine the olive oil, lemon juice, and seasonings in a mixing cup and transfer the mixture to the sheet pan.
Move the sheet pan to the oven and roast for 25 to 30 minutes.
Sprinkle diced cilantro on the top, transfer to meal prep bowls, or serve and enjoy!