Follow these steps for creamy, NOT grainy, mac and cheese. Add processed cheese! Cue the gasps.  I know some of you are skeptical, but trust me. The American cheese or Velveeta melts so much better than sharp cheddar, so using both creates the perfect creamy texture. Sharp cheddar for flavor and American cheese for texture.  Shred your cheddar cheese by hand. Pre-shredded cheese is packaged with anti-caking agents, which don’t let the cheese melt as smoothly. Avoid the graininess, buy the block! Add the liquid to your roux (cooked butter and flour mixture) slooooowly. If you add it too fast and don’t whisk to incorporate it as you go, you’ll get grainy clumps AND your sauce will be thin and watery. Patience you must learn! Add the cheese to your pasta in batches. You might be tempted to dump it in all at once, but if you don’t like grainy, lumpy mac and cheese, be patient and add about one third of the cheese at a time.