Evaporated milk was developed as a shelf-stable alternative to fresh milk in the 19th century. However, it isn't a 1:1 replacement for milk when you're cooking.
To use it like fresh milk, dilute it with water using a 1:1 ratio. Not ideal for baking, it's delicious in coffee, oatmeal, mashed potatoes, or milkshakes as a milk replacement.
Evaporated milk will also save you the challenge of making a roux, saving you time. It provides thickness and concentrated flavor with way less stirring.
Canned evaporated milk is a fantastic substitute for heavy cream, with a little extra flavor and less than half the calories as a result of the way it's reduced.
Since heat is used to make evaporated milk, the proteins in the milk become resistant to clumping, which will prevent it from curdling when you pour it into your soup.
The more concentrated fat and protein in evaporated milk will help to emulsify your melted cheese, which will prevent any clumps or grease from forming.
When making a creamy casserole base, you're essentially creating condensed soup from scratch. Evaporated milk will give you the thick, creamy consistency you need.
Instead of the complicated work of making a roux, combine evaporated milk with cornstarch to create a slurry that will thicken things up as everything cooks.