Overnight Slaw

Ingredients

• 3 1/2 pounds green cabbage, cut into 1-inch chunks
• 1 (1 1/4 pounds) Vidalia or other sweet onion, cut into 1-inch pieces
• 1 pound carrots, cut into 1/2-inch pieces
• 3 celery ribs, cut into 1/2-inch pieces
• 1 cup sugar
• 1 cup distilled white vinegar
• 3/4 cup peanut oil
• 1 teaspoon dry mustard powder
• 1 teaspoon celery seeds
• 1 teaspoon kosher salt
• 1/2 cup flat-leaf parsley leaves, chopped