1. Heat oil in a large frying pan over medium heat. Add onions and salt; cook for about five minutes, until translucent.
2. Add garlic and cabbage, and cook for an additional 10 minutes, until softened.
3. Add pastrami, brown sugar, mustard, soy sauce, and hot sauce. Stir to combine.
4. Cook over low heat for at least 20 minutes, preferably 40–60 minutes, stirring occasionally, until the mixture is golden brown and fragrant. Set aside to cool completely.