In a medium pot, cook macaroni according to package instructions; reserve 2 cups of cooking water before draining.
In a large skillet, brown hamburger meat over medium-high heat until there is no more pink remaining; drain off excess grease.
Return pan to burner and deglaze with 1/2 cup water, scraping the bottom of the pan to loosen any bits off of the bottom.
Lower heat to medium and stir in cream cheese and evaporated milk.
Gently whisk meat mixture over medium heat until all of the cream cheese is melted and incorporated.
Stir in cooked macaroni.
Use some of the cooking water, a little at a time, to thin and spread the sauce, if needed.
When you have the desired consistency in your sauce, remove from heat and gently stir in grated sharp cheddar cheese, one handful at a time, stirring between additions.
Adjust seasoning with salt and pepper to taste.
Serve warm.
Notes
Be sure to remove from heat before adding the cheddar cheese so that it melts smoothly into the sauce.