Bisto parsley sauce - 190g tub which is enough for around 20 portions. Goes great with any fish dishes. Preparation and Usage - For 4-6 servings put 4 heaped dessert spoons in a measuring jug. - Add boiling water up to the 250ml mark. - Stir until it thickens - and that's it: so simple! For a richer, creamier sauce use 250ml of boiling milk instead of water.