Step 1

Wash and dry the squash, zucchini and peppers.

Step 2

Cut off the stems and slice the squash and zucchini into large chunks, discarding the seeds.

Step 3

Remove the stems, seeds and veins from the bell peppers and cut into chunks.

Step 4

Peel the onions and cut into chunks.

Step 5

Working in batches, add the vegetables to a food processor, processing until finely chopped.

Step 6

Place the chopped vegetables in a bowl.

Step 7

Sprinkle salt over the vegetables and stir to combine.

Step 8

Cover and set aside for 1 hour.

Step 9

Thoroughly rinse the vegetables and drain well. Squeeze out excess liquid from the chopped vegetables. It's best to do this over the sink using your hands. Alternately, you can place the vegetables in a cheesecloth or flour sack towel to squeeze out the liquid over the sink.

Step 10

Place the drained vegetables in a bowl and set aside while you prepare the brine.

Step 11

In a large dutch oven, add the sugar, mustard seeds, celery seeds and black pepper.

Step 12

Mix in apple cider vinegar and place over high heat. Bring the mixture to a full boil, stirring often.

Step 13

Spoon in the chopped vegetables and return to a boil, stirring occasionally.

Step 14

Lower to simmer, cook for 15 minutes, stirring often.

Step 15

Remove from heat.

Step 16

Spoon into sterilized canning jars.

Step 17

Wipe the tops of the jars and add sterilized lids and rings. Do not over tighten.

Step 18

Prepare a large canning pot with boiling water.

Step 19

Carefully lower jars into hot simmering water, making sure the jars are covered completely with water.

Step 20

Bring to a boil. Cover and processing for 15 minutes.

Step 21

Carefully remove the jars and allow to cool to room temperature.

Step 22

Tighten the lids and store in a cool pantry cabinet up to 1 year.