Butternut Squash With Pistou without roast beef

1 1/2 pounds butternut squash or other winter squash 3/4 teaspoon olive oil or canola oil 3 stalks celery chopped * 2 small onion diced 2 small carrots diced[...]

2 onions , chopped finely (or 1 large) 1 butternut squash, peeled, deseeded and cut into cubes 2 large carrots , peeled and cut into pieces 3 garlic cloves ,[...]