Sweet Zucchini Relish

Place zucchini and onion in a large, non-metallic bowl; sprinkle salt on top. Use your hands to evenly mix salt with zucchini. Cover and refrigerate overnight.

Drain zucchini in a colander and rinse well with cool water. Squeeze out excess water; set zucchini aside.

Place sugar, vinegar, red and green bell pepper, and cornstarch into a large pot. Add celery seed, nutmeg, turmeric, and black pepper. Stir to combine, then add drained zucchini. Bring to a boil over medium-high heat; reduce heat to medium-low and simmer 30 minutes.

Meanwhile, sterilize seven 1-pint jars and lids. Pack relish into sterilized jars, making sure there are no spaces or air pockets. Fill jars all the way to the top. Screw on the lids.

Place a rack in the bottom of a large stockpot and fill halfway with boiling water. Carefully lower jars into the pot using a holder. Leave a 2-inch space between jars. Pour in more boiling water if necessary, until the tops of jars are covered by 2 inches of water. Bring water to a full boil, then cover and process for 30 minutes.

Remove jars from the pot and place on a cloth-covered or wood surface, several inches apart, until cool. Once cool, press the top of each lid with a finger, ensuring that seal is tight (lid does not move up or down at all).