In a large pot, heat the butter and fresh thyme together. Then as the butter begins to foam, add the diced onion, crushed garlic, and salt. As they begin to soften then add your green peas to the pot. Cook the green peas until they soften slightly, then add your broth. Cook the soup for about another 30 minutes, before the peas turn dark green. You want to keep the nice bright color of the peas intact.

Transfer the soup to a blender, blend until the entire soup is smooth. If you like to have some peas in your soup don't blend it as much. Once blended, transfer the soup back to the pot and then stir in your heavy cream. Cook for another 10 to 15 minutes so you have a nice thick soup.