Creamy Summer Squash and Basil Soup

1 Cup chopped onion
2 TBSP oil
6 Cups of sliced summer squash
1/4 cup minced fresh basil
2 tsp salt
1 tsp white pepper
4 cups of vegetable stock
1/2 cup white wine
4 cups heavy cream

Saute the onion, and squash in the oil with salt and pepper until the onion are translucent.  Add the basil and suatee for a minute longer.  Add stock and wine and simmer for about 10 minutes.  Add cream and simmer for about 10 minutes longer.  Puree and serve chilled.