Rinse 1 ½ lb Brussels sprouts under cold water hands. Pat dry paper towels. Cutting board chef's knife trim tough bottoms slice half lengthwise flat sides even. Bowl dump.
Drizzle 3 tbsp olive oil over sprouts bowl. Sprinkle 1 tsp garlic powder ½ tsp salt ¼ tsp pepper measuring spoons. Toss hands rub shiny 30 seconds coat. Fold ½ cup parmesan spoon sticks.
Preheat oven 425°F middle rack. Parchment line Nordic Ware half-sheet. Spread sprouts cut sides down single layer tongs no overlap. Roast 22 minutes edges crispy charred golden.
Mitts grab Nordic Ware half-sheet. Drizzle 1 tbsp lemon juice spoon over hot. Toss tongs gentle brightens. Serve scoop spoon hot.