Microwave cherry relish

Ingredients

• 1 tbs olive oil
• 1 medium red onion, peeled and finely chopped
• 2 tsp freshly-grated ginger
• 1⁄2 tsp ground cinnamon
• 750g cherries, pitted and halved
• 1 medium apple, roughly chopped
• pinch salt
• 1 cup raw sugar
• 1⁄2 cup red wine vinegar