In a large dutch oven or heavy bottomed pot, melt butter over medium heat with olive oil.
Add onion, celery, carrots, garlic, rosemary and thyme; cook until vegetables begin to soften, stirring several times, about 5 minutes.
Add potatoes, vegetable stock, and bay leaf. Raise the heat to medium high and bring to a simmer, then lower the heat back to medium and simmer for 8-10 minutes or until the potatoes are halfway cooked.
Add zucchini and corn; simmer for additional 8-12 minutes or until the vegetables are completely tender.
Discard the bay leaf and transfer 2 cups of chowder to a food processor or blender; puree until smooth. Stir the mixture back into the pot. Add heavy cream and goat cheese and cook just until heated through and goat cheese is evenly distributed. Season with salt and pepper to taste.
Serve garnished with fresh chopped basil and toasted bread.