Vegetable Soup with butter

1 Pint olive oil 8 oz butter 2 lbs onions , thinly sliced 2 lbs carrots , small dice 2 lbs celery , small dice 2 lbs, 4 oz russet potatoes, peeled, small dice[...]

3 cups peeled butternut squash or 3 cups acorn squash , cut into 1/2-inch cubes 2 cups sliced fresh mushrooms 2 (14 1/2 ounce) cans diced tomatoes , undrained[...]