Prepare Ingredients: In a food chopper, briefly grind the red cayenne pepper and set aside. Then, grind the shallots until smooth.
Cooking: Heat oil, add ground shallots, red cayenne pepper, and lime leaves. Sauté over medium-high heat until fragrant. Then add salt, mushroom broth, MSG, sugar, and water. Reduce heat and cook until slightly dry.
Serving: Serve the onion chili sauce as a complement to your meals.