Preheat your oven to 400°F (200°C). Slice the top off the garlic bulbs to expose the cloves, drizzle with olive oil, wrap in foil, and roast for about 30-40 minutes until soft and fragrant. Let cool slightly.
Meanwhile, peel and dice the potatoes into small, even chunks to promote even cooking. Place them in the slow cooker.
Once the garlic has cooled enough to handle, squeeze out the soft roasted garlic cloves into a small bowl and mash them into a smooth paste. Add a bit of olive oil if needed to help smooth it out.
Pour the vegetable broth over the diced potatoes in the slow cooker. Stir in the mashed roasted garlic to evenly distribute its rich aroma and flavor.
Cover the slow cooker with its lid and cook on low for 6 hours, or until the potatoes are very tender and easily mashable. The house will fill with a wonderful roasted garlic scent.
Once cooked, use an immersion blender directly in the slow cooker—or transfer the mixture to a blender in batches—to blend until smooth and creamy. Be careful with hot liquids.
Return the blended soup to the slow cooker if needed, then stir in heavy cream for extra richness. Season with salt and black pepper to taste.
Adjust the seasoning if necessary, adding more salt, pepper, or a dash of herbs. Let the soup heat through for a few more minutes.
Test the soup’s consistency and seasoning, then ladle into bowls. The soup should be velvety, fragrant, and piping hot, ready to enjoy.
