Combine Ingredients: Add the diced fresh mango, plain non-fat yogurt, milk, white sugar, and optional cinnamon and ground cardamom to the bowl of a blender.
Blend Until Smooth: Puree the mixture until it reaches a completely smooth consistency.
Serve Immediately or Chill: Pour the Mango Lassi into serving glasses and serve immediately, or place it in the refrigerator to chill for 30–60 minutes before serving.
Store Leftovers: Transfer any remaining Mango Lassi to an airtight container or bottle and refrigerate for up to 24–48 hours.
Stir Before Serving: Before consuming refrigerated leftovers, shake or stir the lassi well to recombine the ingredients.