Choose a large pot, add tallow and coconut oil and simmer until melted.
Add chopped onion, garlic, salt and pepper - sautee for a few minutes until softened.
Add the chopped brocolli and cauliflower, chicken stock (I normally make this separately and store it in the freezer in mason jars until I need it) and the coconut milk.
Cover and allow to cook on low for about 45 minutes, check on it regularly.
Blend with a hand blender after it's cooked, I usually allow it to cool a little too so I don't get hot splashes.
I love to store portions in the freezer in mason jars and put in the vitamix on the hot soup setting when I feel like it.