In a small saucepan over medium heat, sauté garlic and ginger in a little oil (or coconut milk) for 1 minute until fragrant.
Add peanut butter, coconut milk, soy sauce, lime juice, brown sugar, red curry paste, cumin, and red pepper flakes. Whisk until smooth.
Cook on low heat for 3–5 minutes, stirring frequently, until the sauce thickens slightly. If too thick, add water 1 tbsp at a time.
Taste and add more lime (for tang), sugar (for sweetness), or soy sauce (for saltiness) as needed.
Serve: Use warm or at room temperature. Garnish with chopped peanuts and cilantro if desired.
