Heat a sauce pan over medium low heat till warm, then add butter.

Add the spices to the pan once the butter is melted. Toast the spices for a minute.

Add the flour then add the milk in 100ml increments, stiring regularly so that no lumps remain.

Once all the milk is added and no lumps remain, add the salt and stir in.

(Optional) You can increase the heat to medium and let the sauce reduce if you prefer it thicker.