Trim and halve the brussels sprouts. Using a vegetable peeler, peel strips of lemon zest, then coarsely chop.

In a skillet, heat 3 tablespoons olive oil over medium-high. Add the brussels sprouts, season with salt and pepper, and arrange cut side down. Cook until browned underneath, about 3 to 5 minutes. Add red-pepper flakes, stir, and cook until crisp-tender, 2 to 3 minutes. Transfer to a bowl.

In the same skillet, heat 1 tablespoon olive oil over medium-high. Add gnocchi, cook until golden brown on one side, 2 to 4 minutes. Add butter and honey, season with salt and pepper, and cook, stirring, until golden, nutty smelling, and foaming, 1 to 2 minutes. Stir in brussels sprouts until warmed. Serve with grated Parmesan.