• Chop the cored green tomatoes, white onion, and jalapeño peppers by hand or with a food processor. Mix together in a large bowl.
• In a medium saucepan over medium-high heat start cooking the green tomatoes, onion, peppers and salt. Add sugar, vinegar, Dijon, celery seeds, and nutmeg to the pot and stir until the sugar is dissolved. Bring the mixture to a gentle boil over medium heat. Then reduce heat to low and simmer, occasionally stirring until the vegetables are tender and the juices from the tomatoes have evaporated, about 15 minutes.
• Divide the relish between 2 pint-size mason jars. If you are canning, be sure to sterilize the jars, seal the lids, and then follow the water bath canning method. Alternatively, you can store the green tomato relish in the refrigerator for up to 2 weeks.

To Make Ahead

• Cover and refrigerate for up to 2 weeks.