Milk, and milk products, can be used to flavor other food, apart from being main ingredients in a variety of dishes.
Milk has been used in cooking since the first milk producing animals were domesticated. Milk is a main ingredient in a wide range of dishes, but we are more interested here in the use of milk and other derivatives to flavor other dishes, not as main ingredient.
Milk’s by-products, like creams and yogurts, are used to add a special and distinctive flavor to many sweet and savory foods.
In cooked dishes, always add creams and yogurts towards the end, and make sure the heat is low to avoid curdling.
Butter - It is used to thicken many sauces, and it gives them a very particular flavor. As much as one can love olive oil, there are some dishes that definitely need the flavor butter adds.
Buttermilk - Buttermilk is the sour residue left over from butter making.
Cheese - Every cheese has its own distinctive flavor, and they impart that flavor to the food when they are added. A simple broccoli and cheese soup is a nice warmer in the winter -we could use any kind of cheese, but the flavor is completely different if we use blue cheese. The same could be said about a blue cheese dressing.
Cream - It is the fat to the surface of the milk as it cools, which is skimmed to produce butter or cream. Fresh cream will keep 2-3 days in the fridge; keep covered or it hardens. Take care not to over whip cream when using it, in case it turns buttery.
Sour cream - Sour cream is cream inoculated with a lactic acid culture to give it a slightly acid flavor. It can be substituted by plain cream with a drops of lemon juice.
Sour milk - Sour milk products are made into a number of cooling drinks. Think of kefir, for instance.
Yoghurt - Most yogurts keep for 5 days in the fridge. Enthusiasts make their own yogurt; home made yogurt will keep 10 days in the fridge.