August Corn Chowder

Ingredients

• 2 tablespoons unsalted butter
• 1 medium onions (finely chopped) or 2 shallots (finely chopped)
• 3 garlic cloves, minced
• 1 teaspoon dried whole thyme (chopped) or 2 teaspoons fresh thyme (chopped)
• salt
• pepper
• 3 1/2 cups reduced-sodium chicken broth
• 1 1/2 cups water
• 4 medium potatoes (like Yukon Gold, un-peeled and diced)
• 5 ears corn, kernels scraped off
• 2 medium beefsteak tomatoes, chopped
• 1 tablespoon red wine vinegar
• sour cream
• fresh tarragon (chopped, for garnish)