In my house, it's scalloped potatoes. My kids jokingly call it "a heart attack on a plate", but there's never any left, and it is my most requested item whenever I'm invited to a potluck.
In an 9x13 baking dish, I layer thinly sliced russet potatoes, a generous amount of grated jack cheese and velveeta, and sprinkle on a heaping tablespoon Powdered Knorr Chicken Bouillon (It really does have to be Knorr...it has seasonings in it that other brands do not). Repeat the layers one more time, drizzle with a half pint of heavy whipping cream so that it runs between the layers and distributes the bouillon powder throughout. Bake at 350 for an hour, then uncover and bake a few more minutes to lightly brown the top. Let cool for about 15 minutes before serving to let the sauce thicken up.
Alternately, I sometimes substitute cooked pasta for the potatoes.