Preheat the oven to 425°F. Line a rimmed baking sheet with parchment paper. Spray the parchment paper with oil.
Wash and dry the sprouts. Remove any damaged outer leaves. Cut them in half.
Place the Brussels sprouts in a large bowl. Add the melted butter, honey, salt, pepper, and garlic powder. Use a large spoon or your hands to coat the sprouts evenly and thoroughly.
Arrange the sprouts in a single layer on the prepared baking sheet. Roast them for 15 minutes.
Remove the pan from the oven. Flip the sprouts to the other side (I use two teaspoons). If any of them is already deeply browned, remove it to a plate. Wipe off any spots with caramelized honey on the pan to prevent them from burning.
Return the pan to the oven and roast the sprouts until tender and browned, for 10-15 more minutes. Serve immediately.
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Notes
A trick to make the sprouts crispy is to use pre-washed bagged sprouts. This ensures that they'll be completely dry. If you need to wash them, dry them thoroughly. Otherwise, they will steam rather than roast.
You can slice large sprouts into three parts instead of two.
Some sprouts will be ready faster. Remove them to a plate and keep roasting the others.
For restaurant-level sweetness, use two tablespoons of honey.
You can keep the leftovers in a sealed container in the fridge for up to four days. Reheat them in a low oven (300°F) to crisp them back up. You can also freeze them for up to three months.