North Croatian Simple Tomato Sauce - cooking recipe

Ingredients

500 g tomatoes (strained juice or package 500 g)
1 tablespoon oil (or lard)
2 teaspoons flour
2 g celery leaves (or one sprig green celery)
2 tablespoons brown sugar
6 g salt
1/2 cup water

Preparation

Heat oil and add flour. Fry until slight brown (or 1-2 minutes). Add gently some water and make creamy liquid.
Add all tomato juice, salt, sugar and celery sprig. Add the rest of the water.
It is cooked after 20 minutes, but you can cook more if you want (do not burn it). Remove celery sprig before serving.