Step 1

Melt the butter in a soup pot set over medium heat. I use a 5-quart Dutch oven.

Step 2

Add in the olive oil.

Step 3

Add in the sliced leek; season with salt and pepper, and saute for about 6 minutes, or until softened. Stir frequently.

Step 4

Stir in the garlic and cook for 15 seconds.

Step 5

Stir in the cubed potatoes; cook for 20 seconds.

Step 6

Pour in the broth and add in the thyme sprigs; bring to a boil.

Step 7

Cover with a lid and lower the heat to a gentle simmer.

Step 8

Cook for 22 to 25 minutes, or until potatoes are very soft.

Step 9

Remove from heat.

Step 10

Remove thyme sprigs from the soup.

Step 11

Using an immersion blender, blend the soup until smooth.

Step 12

Stir in the heavy cream.

Step 13

Taste for salt and pepper, and adjust.

Step 14

Ladle soup into bowls.

Step 15

Garnish with croutons, parsley, and chives.

Step 16

Serve.