1. Preheat oven to 400 degrees F and wrap garlic heads in foil with a drizzle of olive oil, then roast 40 minutes until soft

2. Place potatoes in a large pot, cover with cold salted water, bring to a boil and simmer 15 minutes until tender, then drain well

3. Using a potato ricer or masher, mash the hot potatoes until smooth or slightly rustic

4. Squeeze roasted garlic cloves into the potatoes and stir to combine

5. Add softened butter, warm cream, and sour cream, stirring gently until creamy and smooth, seasoning with salt and pepper

6. Transfer mashed potatoes to a buttered baking dish and press plastic wrap onto the surface, then refrigerate up to two days

7. To reheat, add a splash of cream, cover with foil and bake at 325 degrees F for 25 minutes, stirring halfway through

8. Meanwhile, melt butter in a skillet, add sourdough bread crumbs and toast until golden, then sprinkle on reheated potatoes before serving