Heat the butter and oil in a large pot over medium heat.
Add the leeks and saute until softened.
Add the cauliflower and parsley. Turn the heat to very low and cover the pot. Cook for 15 minutes.
Add the stock and turn the heat up to medium-high. Simmer for 10-15 minutes or until the cauliflower is tender.
Puree the soup with an immersion blender or by carefully transferring some of the cauliflower and liquid to a blender. Always vent the lid and use caution blending hot liquids. Return the puree to the pot (if using a blender).
Stir in the heavy cream. Season to taste with salt and pepper.
Notes
Nutrition: This makes about 4 quarts of soup. The serving size is approximately 1.5 cups. There are 6.7 NET carbs per serving.Servings: This is a large batch recipe. You can decrease the amount by clicking the number next to servings and changing that.Storage: Store in the refrigerator for 5-6 days or freeze for up to 6 months.Reheating: Reheat covered in the microwave or in a saucepan until hot.