Grandma Alice's Tomato Relish

Ingredients

• 2.75 kg green (and/or red) tomatoes (our preference is all red)
• 910 g onions
• 2 Liters water (approximate)
• 1/2 cup salt
• Vinegar
• 910 g sugar
• 2 tablespoons curry powder
• 6 teaspoons dry mustard
• 3 tablespoons cornflour (may need up to 6 tbsp)
• 1 teaspoon mace
• 1 teaspoon pepper
• 1 teaspoon ground cloves
• 1 teaspoon cinnamon
• 1 teaspoon ground ginger
• 1 teaspoon nutmeg