Peel the vegetables and cut into 1-inch chunks. Add the oil to a large skillet and heat over medium/high heat. Once shimmering, stir in the ginger and garlic and cook until fragrant, about 1 minute. Add in the vegetables and ½ teaspoon salt, tossing to coat in the oil. Continue cooking over medium/high heat, stirring occasionally, until the vegetables are tender and beginning to brown, about 10 minutes. Reduce the heat to medium and stir in the This Little Goat went to Hong Kong sauce and red pepper flakes, if using. Continue cooking over medium/low heat, stirring occasionally, until the vegetables are tender and beginning to caramelize, about 12-15 minutes more. Remove from the heat and stir in the chopped parsley. Serve warm or at room temperature.