Combine the coconut, chilies, salt, cashews, ginger, granulated garlic, cumin seeds, and lemon juice in a blender. Add as little water as possible to allow it to blend. Blend to a consistent texture with no lumps.
For the tadka, heat oil in a small pan. Add mustard seeds and hing. Let it toast for a few seconds. Then add dal. When it starts to turn lightly brown, add curry leaves. Let those cook for a few seconds and remove from heat.
Pour or spoon the tadka over the top of the chutney.
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Notes
The tadka is completely optional. It adds some aroma and texture but many people do not add it to their everyday coconut chutney.