Pumpkin and Sunflower Seed Savory Biscuits

Name: Pumpkin and Sunflower Seed Savory Biscuits
Ingredients: 4 red onions, chopped; 50g (1¾ oz) caster sugar; 1 tsp caraway seeds, toasted and ground; 50ml (2 fl oz) red wine vinegar; 50ml (2 fl oz) red wine; 1-2 tsp blackcurrant cordial, to taste; 140g (5 oz) rye flour; 70g (2½ oz) wholemeal flour; 70g (2½ oz) plain flour; 55g (2 oz) pumpkin seeds; 55g (2 oz) sunflower seeds; 25g (1 oz) chives, chopped; 1 tsp English mustard powder; 1 tsp table salt; 1½ tsp baking powder; 30g (1 oz) sun-dried tomato paste; 3 tbsp olive oil; mature cheddar cheese, to serve