/ck/ - Food & Cooking

Why is my mac and cheese grainy and solid? I want creamy and a bit liquidy, but a bit sharp too.
Last time I used 1 lb pasta, pre-boiled 2/3 of the way, and 3 8 oz bricks of sharp cheddar grated for the sauce. I blended the sauce till smooth, baked it in the oven for less time than last time (26 min total) and it is grainy and not as soupy as I would like.
Do I just have to bite the bullet and buy velveeta? I have my own emulsifying agents, the sauce didn't break, just was grainy, perhaps from the sharp cheddar?
What am I doing wrong? I know I need to use lower oven heat (used 400f last time, too much).
Maybe some of the cheese needs to be sprinkled on top, not mixed into the sauce?