European Kitchen - Cream of mushroom soup

Recipe Ingredients:

3 tablespoons butter

2 tablespoons olive oil

1 finely chopped onion

1 cup leeks

3 cloves garlic, crushed

1 sprig fresh thyme

600g mushrooms

1/3 cup dried mushrooms

1/2 tablespoon onion powder

1 tablespoon brown sugar

1/4 teaspoon nutmeg

6 cups chicken broth

1/2 cup cold milk

5 tablespoons cornstarch

1 cup heavy cream

1/2 cup chives (optional)

Salt and pepper