Bring a large pot of salted water to a boil. Add the brussels sprouts and cook until bright green, 2 minutes. Drain well and pat dry.
In a large, deep skillet, heat 3 tablespoons of the oil until shimmering. Add half of the garlic and half of the brussels sprouts and cook over high heat undisturbed for 1 minute. Add half of the crushed red pepper, season with salt and cook over moderate heat, stirring a few times, until the brussels sprouts are browned and tender, about 3 minutes. Transfer to a serving bowl. Repeat with the remaining oil, garlic, brussels sprouts and crushed red pepper. Serve warm.