Homemade Tomato Sauce - cooking recipe

Ingredients

1 tbsp olive oil
1 None large onion, roughly chopped
2 tbsp dark brown sugar
3 (13.5 oz) cans chopped tomatoes
1/4 tsp ground allspice
1/2 tsp celery salt
2 tbsp tomato puree
1/3 cup white vinegar

Preparation

Heat oil in a large saucepan over medium heat. Cook onion, stirring, until soft. Add sugar, tomatoes, allspice and celery salt. Bring to a boil then reduce heat and simmer, stirring occasionally, for 30 mins, or until mixture thickens. Stir in tomato puree and vinegar. Cook for 5 mins then let cool slightly.
Blend or process sauce until smooth. Push through a fine-mesh sieve into a bowl. Discard solids. Serve sauce cold.