In a large stockpot or Dutch oven, melt coconut oil over medium heat. Add onions, carrots, celery, bay leaf, and thyme. Cook, stirring occasionally, until tender, about 3-4 minutes. Add roasted cauliflower, garlic, coconut milk, and 1 cup of vegetable broth to the blender and blend until smooth. Use a knife to remove the kernels from the ears of corn and add them to the sautéed vegetables. Pour the blended cauliflower to the pot and stir to combine. Add more vegetable broth until it reaches the desired consistency. Bring to a gentle boil and simmer for 10 minutes. Season with salt and pepper to taste.