First Step: Prep and mise en place Preheat the oven to 425 degrees Fahrenheit and line a baking sheet with parchment paper. While the oven heats, trim any dry or woody stem ends from 1 pound of Brussels sprouts and remove damaged outer leaves. If some sprouts are much larger than others, halve the big ones so pieces are similar in size. This helps everything roast evenly. Pat the sprouts dry with a towel if they feel wet; removing surface moisture improves browning.

Second Step: Season and arrange Place the trimmed sprouts in a mixing bowl. Drizzle with olive oil and sprinkle with sea salt and freshly ground black pepper. Toss until evenly coated. Arrange the sprouts on the prepared baking sheet in a single, even layer with the cut sides facing down. Scatter any loose inner leaves on the sheet too; they become crispy little bites. Avoid crowding the pan so the sprouts roast rather than steam.

Third Step: Roast at high heat Slide the sheet into the preheated oven and roast for 20 to 30 minutes. Timing depends on the size of your sprouts: smaller ones finish closer to 20 minutes while larger pieces may need the full 30. Check at the 20-minute mark and use tongs to turn any pieces that need more browning. The goal is tender centers and deep golden-brown edges.

Fourth Step: Make the optional lemon Parmesan seasoning While the sprouts roast, combine the optional seasoning if you like a bright finish. Mix 1 tablespoon lemon juice with 2 teaspoons lemon zest, 1 tablespoon Parmesan cheese (or 1/4 cup shaved), and 1 tablespoon fresh thyme leaves. Have a pinch of red pepper flakes and some chopped parsley ready for garnish. Keep this mix separate until the sprouts are warm so delicate ingredients do not burn.

Fifth Step: Toss and finish When the sprouts are out of the oven and still hot, transfer them to a serving bowl. If using the lemon Parmesan seasoning, toss the warm sprouts with the lemon mixture and Parmesan so the cheese slightly melts and the zest brightens the flavor. Add parsley and a pinch of red pepper flakes to finish. Serve immediately while the outsides are still crisp.