2. Pour the dry elbow macaroni evenly into the bottom of the casserole dish, spreading it into an even layer for uniform cooking.
3. Sprinkle the kosher salt over the dry pasta, then scatter the butter pieces evenly across the top. This will allow the butter to melt into the milk and pasta as it bakes.
4. Pour the cold whole milk slowly and evenly over the dry macaroni, ensuring all the pasta is moistened and mostly submerged. Gently press any pieces that are sitting on top down into the milk with the back of a spoon.
5. Sprinkle about 1½ cups of the shredded cheddar cheese evenly over the milk and pasta mixture, reserving the remaining ½ cup for later. Avoid stirring; keeping the layers helps create a creamy texture as it bakes.
