To determine the amount of flour needed, it would depend on the recipe and the desired consistency or ratio of milk to flour. Without more information, it is difficult to provide an accurate answer. However, a common ratio for making a basic white sauce (béchamel) is 1 tablespoon of butter, 1 tablespoon of flour, and 1 cup of milk. This would give you a ratio of approximately 2 tablespoons of flour for every cup of milk. Using 15 oz of milk is approximately 1.875 cups. Multiplying this by the ratio of 2 tablespoons of flour per cup of milk, you would need around 3.75 tablespoons of flour.
