In a mixing bowl, whisk the yogurt until smooth.
Add the grated cucumber, cumin powder, salt, chopped mint or cilantro (if using), and black pepper. Mix well to combine.
Taste and adjust seasoning, adding more salt or spices if needed.
Refrigerate the raita for at least 30 minutes before serving to allow the flavors to meld.
Sprinkle rosted cumin seeds on top just before serving.
