Peel and cut potatoes in half.
Boil them in salted water till barely fork-tender.
Drain and let them cool.
Slice into 1/4-3/8” thick pieces.
In a greased 9×13″ pan, Layer: potatoes, seasoning salt, onion cheese top with cream and repeat 2 more times omitting the cheese on the top layer for now.
When all 3 layers are in the pan, pour half-n-half (or an equal amount of milk and heavy cream) over it all till about half way up the potatoes.
May hold in the refrigerator at this point, tightly covered.
Bake at 350° F. till hot and bubbly, 1-1/2 hours.
Just before serving, uncover and top with the remaining layer of shredded cheddar cheese and heat till melted and bubbly.
Let set 15 minutes, preferably, before serving to let the potatoes absorb more of the liquids and meld the flavors.
