Line a standard loaf pan with plastic wrap, making sure it's pressed into the corners.
Place the water in a size appropriate pan with a heavy bottom, OR a double boiler (if you don't want to watch it as closely). To me, faster is better, & mush cooks up over low heat very nicely w/ the occasional stir in a thick bottomed pot. If you have doubts, use the double boiler.
Add the corn meal and salt to the cool water and place the pot on med- high heat. - If you want scrapple, add the sausage when you add the cornmeal & put your hand in the pot to break up the sausage very thoroughly.You don't want chunks of meat because it will be much harder to slice later.
When the mush begins to boil, turn heat down to medium-low, cover, and stir every few minutes w/ a spatula to keep it from sticking and burning.
Cook 20 minutes, stirring frequently, remove from heat and pour into the plastic lined loaf pan.
Cool 10 - 15 minutes, cover w/ plastic, finish cooling on the counter, and chill at least four hours, or up to a week.
Turn the loaf out onto the top covering of plastic wrap and slice 1/4 to 1/2 inch thick, using a thin, sharp knife.
Fry slices in a non-stick pan in the fat of your choice; just a drizzle in a non-stick pan does nicely. Fry over med to med low heat till the slices are nicely browned. I take my time when frying this, you want to develop a nice crunchy crust over the soft mush inside, and on high heat you'll brown it before it gets the texture we like.
Serve hot w/ honey, syrup, or w/ butter and hot sauce. Good cold too.
Mush cannot be frozen because the formation of ice crystals causes it to break up when thawed.