Melt the butter in a large pot. Add the onion, celery, and carrots. Stir. Add the seasonings and cook for a minute.
Next, add the potatoes to the pot and stir well. Add another layer of salt & pepper if desired. Stir and cook a minute. The onions should be starting to turn translucent.
Add the chicken broth and bring the soup to a boil. Reduce the heat and cook until potatoes and carrots are fork tender.
Once the potatoes and carrots are done, add the evaporated and milk. Stir and cook until milk is heated. Sample and adjust seasoning if needed. Add 1 tablespoon or so of chopped parsley if you wish. Serve.
Notes
4 cups of diced potatoes is about 4 to 6 potatoes. I use russet potatoes.Using the evaporated milk creates a nice creamy base to this soup. Fresh parsley adds a nice touch of freshness. I like to add the salt and pepper in layers as I add ingredients. I find it works better then trying to adjust the seasoning only when getting ready to serve.