I just worked this out on the fly, and it was pretty good!
I still have a half dozen big cans of Campbell’s Chunky Clam Chowder, but I also had 2 small cans 10 oz (5 oz drained wt.) of just clams. Clearly having the soup already made in a can is easier by far, but bought the clams before finding the soup. So decided I ought to use them up.
You can use fresh milk, but reconstituted dry or evaporated condensed works fine too. Dumped the clams (liquid and all) into a sauce pan with a sprinkle of garlic granules and about a tsp of dried onion flakes. Added 2 Tbs of butter (coconut oil or olive oil instead if no butter) along with reconstituted potatoes (see below) and brought to a simmer. Dumped in one can volume of milk, salt & pepper to taste, and slowly return to the simmer. Simmer until potatoes are soft (just a minute or two) remove from heat and let if stand a minute or three while you get the bowl, crackers, and beverage ready.
For potatoes, I used reconstituted hash browns. Or-Ida Idaho Spuds sells these in little pint sized milk carton like packages. You add boiling water and let it sit 6 minutes, then drain & fry. Well, instead of frying, I added about 4 oz, reconstituted, to the clams, juice & butter. Other dried potatoes could be used, but might need cooking more first if thicker.
If you like celery in your chowder, add some dry celery flakes or very little (it is potent!) celery seed. The dish is amenable to other additions too. Corn, carrots, peas, whatever. I like it more pure with just potatoes, but as you like it.
In general, I’m quite pleased with the result. It isn’t gloppy thick like the canned stuff (if you like that, add about a tsp of flour to the milk before you pour it in and simmer long enough to thicken). It also doesn’t have the high Omega-6 soy or canola oil of the canned soup, nor does it have the GMO ingredients.
I do like being able to make a nice clam chowder using all canned or dry ingredients. I may score some canned ghee (butter) from the Indian grocery store and try that. Other than that, not seeing much I’d change.
Musings from the Chiefio 
Either you misspelled one of the most important ingredients or you left it out: PEPPER. And lots of it.
Excellent recipe. But then if there is one thing to come out of this, it will be new recipies!
I use Chunky soup and add some of this it them when needed. Just sayin, just add clams and boom. dress it as you want after that. Works for me and adds the protein to make a meal for a couple days.
https://www.samsclub.com/p/doxsee-snow-s-ocean-chopped-clams-2-51oz/164786?xid=plp_product_1_3
@Serioso
“salt & pepper to taste,:”
Looks to me like it’s in there… I leave pepper as “to taste” for the simple reason that I like a fair amount and the spouse likes as close to none as possible. So often I make it bland then put a few grinds on my servings of (whatever).
When I’m making a pot just for me, yeah, about a half dozen grinds on the little pepper mill. On that we can agree ;-)
Phil:
Yeah, I’ve been having some fun on the creativity front ;-) Even when I have the “normal” ingredients, I’m trying some of the “make do” approaches.
@Ossqss:
Good point! There’s a whole style of cooking that’s “box plus” or “can plus”. Great way to turn so-so into oh boy!
I generally make my oyster stew and clam chowder with way more good stuff than you get in any canned item. I’ve been known to add oysters to canned oyster stew, too. Then there’s those packaged “noodle and sauce” things where you can add all sorts of meats and cheeses or sautéed mushrooms, onions or olives to kick it up a notch.
My “Tuna noodle casserole” is just that. Kraft or Annie’s mac & cheese, plus a drained can of tuna and some peas. In a baking dish for 25 minutes at medium heat. Sometimes (often) with a layer of shredded cheese added on top.
I also use boxed Au Gratin Potatoes and add diced ham or spam to it, then baked en casserole. Again sometimes with added cheese on top.
For this clam chowder, I was mostly interested in finding out if the potato shreds would work. I already knew that coconut or olive oil can substitute for butter and that canned / powdered milk were reasonable alternatives in Oyster Stew (canned evaporated best). But how to get potato “dice” without fresh potatoes? I’m pleased with the result, though I think using a box of Betty Crocker Au Gratin potatoes might work better.
We’ve gotten rather fond of the hash browns. They work great. So I plan to keep on buying them even when all this has blown over. It’s nice to know they work in soups too ;-)
@E.M. – Where are those dried potatoes located in your store?
I recall seeing them, but I can’t think of the section. I don’t really want to wander around looking for them.
I liked corned beef hash and I keep a few cans of the corned beef around in my emergency rations. Those canned meats are pretty long dated.
I’ve used frozen hash browns with the tinned corned beef a couple of times to make hash, but dried potatoes would be better on the shelf in case of power loss.
The tinned corned beef is perfect for hash as it is minced and pressed into the can. You can slice it or break it down to largish chunks or really mash it up for a nice mince, perfect for hash. Potatoes, corned beef, a frying pan and there you have it.
BTW, all of the tinned corned beef I have bought comes from Argentina. I’ve bought three different brands. Two of the brands were rather salty, but the last one I used to make corned beef and cabbage was not salty at all. I had to add a couple of shakes of on top of my serving. I wish I could remember which of the brands that was, but I tossed the can without paying any attention because I was expecting the same saltiness as the others.
I got them at COSTCO in the same area as other dry boxed goods. Looking at them, it is not Or-Ida brand (my bad) but Idaho Spuds.
https://costco97.com/idaho-spuds-golden-grill-hashbrown-potatoes/
Can’t seem to make chowder anything but a yellowish brown from scratch, wonder what the secret of the canned stuff and restaurants is?
@R.M.:
No secret. I suspect you are doing something wrong. Likely overheating it on too hot a burner..
My chowders are always white. I make sure to never set the burner more than 1/2 of full, and never heat milk beyond s simmer. Stir often.
Milk easily scorches and thickens in the bottom of a pan, so high hest or hotter than a simmer rapidly makes a thick insulating goo on the pan bottom that enhances burning.
Only other likely candidate would be some spice, not in the usual recipies, you add that causes a color chsnge.
Basically, clams and milk heated slowly to a bare simmer will be white. Adding potatoes, salt, even corn will not change that.