In large skillet or sauté pan, heat oil over medium-high heat. Once hot, add blanched Brussels sprouts. Carefully, shake pan so cut sides of sprouts face down. Cook undisturbed for 4 to 5 minutes, until cut sides of sprouts begin to caramelize. Add sliced shallots; stir and continue to cook until sprouts are completely caramelized and shallots are translucent. Cook for another 4 to 5 minutes, or until sprouts are tender. Season with lemon juice, onion powder, and salt and pepper, if using. Stir and cook another 30 to 60 seconds.