1 large sweet red pepper, cut into 1/4-inch strips
1 medium onion, chopped
1 tablespoon salt
1 cup sugar
3/4 cup white vinegar
3/4 teaspoon mustard seed
3/4 teaspoon celery seed
1/4 teaspoon ground mustard
METHOD
Place squash, pepper and onion in a colander over a plate; sprinkle with salt and toss. Let stand 1 hour to drain.
In a large saucepan, combine remaining ingredients; bring to a boil, stirring to dissolve sugar. Add vegetables; return to a boil. Remove from heat; cool completely.
Transfer to a covered container; refrigerate, covered, at least 4 days before serving. May be stored in refrigerator up to 3 weeks.