Preheat the oven to 425°F (218°C). Line a large rimmed baking sheet with parchment paper if desired.
Rinse the Brussels sprouts, trim the stem ends, remove damaged outer leaves, and dry thoroughly.
Halve the sprouts lengthwise. Quarter unusually large ones so the pieces cook evenly.
Toss the sprouts with olive oil, salt, and black pepper in a large bowl.
Arrange them in a single layer on the baking sheet, placing many cut sides down.
Roast for 12 to 15 minutes, then turn the sprouts and roast for another 8 to 12 minutes.
Sprinkle the minced garlic over the sprouts, toss gently, and roast for another 3 to 5 minutes, checking frequently so the garlic doesn't burn. If the sprouts need more time, continue roasting until fork-tender.
Remove from the oven and drizzle with lemon juice.
Taste and adjust the seasoning. Add pomegranate seeds or toasted pecans if desired.
Transfer to a serving platter and serve warm.