Place a small saucepan over medium-high heat until hot. Add the oil, swirling to coat the bottom. Add the garlic and cook, stirring, until fragrant, about 10 seconds. Add the broth, hoisin sauce, peanut butter, fish sauce, and chili garlic sauce and bring to a boil. Reduce the heat to low, and simmer until thickened, 4 to 5 minutes. Stir in the peanuts. Serve the dressing hot, warm, or at room temperature. Store in a covered container in the refrigerator; it will keep for up to 2 weeks.