Here is a very good recipe for a home-made tomato ketchup. Anyone who tries it will have difficulties to put up with the commercial stuff in the future. The basic recipe comes from the book 100 hot and spicy sauces by Sally Griffiths. I have modified the recipe somewhat. This batch makes about 1.3 litres. The combination of fresh and canned tomatoes makes an excellent balance between sweet and sour, but anyone who can get really good and ripe fresh tomatoes will skip the canned ones.
750 g very ripe cherry tomatoes
1 tsp sea salt
2 tbsp extra virgin olive oil
2 large onions, chopped
1 can plum tomatoes
150 ml Muscovado sugar
1 tbsp sea salt
1 tsp black pepper, crushed
1 tsp allspice, crushed
6 cloves, crushed
150 ml apple cider vinegar or malt vinegar
2 tbsp tomato purée
1 lemon, juice of
½ tsp sodium benzoate
Additional tomato purée (see below)
Put the cherry tomatoes on an oven-proof tray. Add the olive oil and 1 tsp sea salt.
Bake in a 250 C/480 F oven plus grill for 20 minutes or until the skins start to turn black. Let cool and remove any sprigs.
Pour the oil from the tray into a pot and heat. Add the onions and the tomatoes. Bring to a boil and add all the other ingredients except the lemon and benzoate.
Let simmer for 40 minutes while stirring occasionally. Remove from heat and add the lemon and benzoate.
Run in a food processor or blender, then pass through a sieve. Add extra tomato purée (abt. 2-6 tbsp) to make a very thick sauce. Mix thoroughly.
Pour into jars and seal. Keep even unopened jars refrigerated. (I don't know how long they will keep, but it's important to only use clean cutlery when taking from the jars). Obviously, the ketchup can be frozen or preserved as well.