The key to this delightfully simple chowder is its slow cooking process. So, please, don't try to rush it.
You're going to need to dice up the onions, carrots and potatoes. You can do that all first, or do it as you go. Its up to you :)
So, take a very large stew pot and pour some oil in the bottom. Turn the heat to medium or a little lower. Throw in the diced onions and toss them around to coat with the oil. Now just leave them alone. Let them caramelize over that low heat. You can stir them, but infrequently or you won't get them caramelized. Oh, and sprinkle a little salt on them so they sweat.
Welcome back to the recipe! Aren't those onions beautiful? Now, Add the diced carrots and just cover with water. I use spring water because our well is sketchy. If you have city/town treated water, do yourself a favour and buy a gallon of spring water. The chemical taste will interfere with the simplicity of flavours in this dish. Okay, I'll see you again soon. Let the carrots cook - until they are done.
See, it takes a long time, but it isn't really that much work, right? Anyway, its time to add the potatoes and let them cook. They are quicker than the carrots were.
Now that your veggies are all cooked and that water has become a delicious vegetable broth it is time to add the liter of cream - mmmmmmmm. . ..cream. I hope you haven't ever turned up the heat because you don't want this at more than a simmer. Take a masher and mash up a little bit of the veggies just to add some thickness to the broth. Don't over do this, just a little mash. You still want lots of chunky veggies in your chowder.
Now add the seafood and clams (whatever kind of seafood you like is fine by me) and they will poach up beautifully in this liquid. Also add that 1/4 cup of butter. Oh yeah. Cause it wasn't fattening enough already.
Season with salt and pepper to taste. (it can take a lot of salt, but add a little at a time because you can always add more but you can't take it out once its in there!)
Serve with rolls and real butter.