Step 1

In a large saucepan, combine the onion, mustard seed, salt, vinegar, ginger, garlic, sugar and the water.

Step 2

Mix to combine and bring to a simmer for 5 minutes.

Step 3

Remove the ginger and garlic from the simmering mixture.

Step 4

Add the mangos, Fresno chilies, and lime rinds to the saucepan and simmer for another 10 minutes.

Step 5

Remove from the heat and refrigerate overnight.

Step 6

Taste and adjust the seasoning, as necessary.

Step 7

Cover and store in the refrigerator for up to 2 weeks.