Slice the tops off the garlic bulbs, drizzle with olive oil, sprinkle with salt, and roast at 400°F (200°C) until soft and golden, about 45–60 minutes.
Add baby potatoes to a pot of well-salted water and boil until fork-tender, about 15–20 minutes, then drain and let dry.
Melt butter in a pan, squeeze in the roasted garlic cloves, mash into a smooth paste, and stir in the reserved garlic oil.
Preheat a baking tray in the oven, place potatoes on it, and smash each potato using a glass or masher.
Brush or spoon the garlic butter evenly over each smashed potato.
Bake at 400°F (200°C) for 25–30 minutes until edges are golden and crispy.
Garnish with parsley, flaky sea salt, and black pepper, then serve immediately.
