Place the potatoes into a medium or large saucepan. Add cold water to the pan until the potatoes are covered by one inch or more. Add 1/2 teaspoon salt. Bring to a boil, then cook until the potatoes are fork-tender (about 18 minutes for russets). Drain through a colander, shaking well to remove excess water.
Meanwhile, heat the butter and cream. Once the potatoes have been cooking for around 12-15 minutes, heat the half-and-half and butter in a small saucepan over medium heat, stirring, until steaming hot (You can also use the microwave).
For smooth mashed potatoes: press potatoes through a ricer or food mill into a large bowl.
For textured mashed potatoes: transfer potatoes to a large bowl and use a potato masher to mash to the desired texture.
Pour the hot cream and butter mixture over the potatoes (if the mixture has cooled, briefly reheat first. It will help melt the cheese). Stir until just combined (don’t over-mix to avoid gummy potatoes), then swiftly stir in 2 cups cheese until smooth. If you want a thinner consistency, drizzle in some additional half-and-half. Add salt and pepper to taste (I used 1/2 teaspoon salt and 1/4 teaspoon pepper).
Serve warm, optionally topped with chives.
Heavy cream or milk may be substituted for the half-and-half. Avoid using nonfat milk for best texture.I recommend using a yellow-colored, sharp cheddar cheese (I used Cabot Seriously Sharp Cheddar). Orange cheese will create an unusual colored mashed potatoes.For best results, the cheese should be completely melted and incorporated into the potatoes. If the hot potatoes and liquid mixture don’t fully melt the cheese, you can microwave the mashed potatoes in 30 second increments, stirring each time, until smooth. You can also do this in a saucepan set over medium-low heat.