From USDA
Piccalilli
6 cups chopped green tomatoes
1-1/2 cups chopped sweet red peppers
1-1/2 cups chopped green peppers
2-1/4 cups chopped onions
7-1/2 cups chopped cabbage
1/2 cup canning or pickling salt
3 tbsp whole mixed pickling spice
4-1/2 cups vinegar (5 percent)
3 cups brown sugar
Yield: 9 half-pints

Please read Using Pressure Canners and Using Boiling Water Canners before beginning. If this is your first time canning, it is recommended that you read Principles of Home Canning.

Procedure: Wash, chop, and combine vegetables with 1/2 cup salt. Cover with hot water and let stand 12 hours. Drain and press in a clean white cloth to remove all possible liquid. Tie spices loosely in a spice bag and add to combined vinegar and brown sugar and heat to a boil in a sauce pan. Add vegetables and boil gently 30 minutes or until the volume of the mixture is reduced by one-half. Re-move spice bag. Fill hot sterile jars with hot mixture, leaving 1/2-inch headspace.For more information see "Sterilizing Empty Jars".

Adjust lids and process pints and half pints 5 min.
NOTE: if you want to skip boiling and sterilizing the jars, use clean jars and process 10 min.

Interestingly enough, you can buy jars of Piccalilli at Dutch grocery stores. I want to know what the difference is between piccalilli and chow-chow.

The USDA recipe posted by LindaLou IS the Chow Chow I remember from growing up in the South (US). It wasn't until years later that I even heard of Piccalilli and I got the idea the two names were interchangeable, but just a few days ago I ran across a recipe from England with lots of mustard powder, cauliflower, tumeric, FLOUR and chunky veggies. It was bright yellow and reads a lot like the Mustard Pickles several people have mentioned on the forum.
It seems to be a Victorian pickle with heavy Indian (as in India) influence... in fact I saw one ad for jarred Piccalilli which said it used to be called Indian Relish.

I think I prefer MY ChowChow.