Preheat your oven to 400 degrees Fahrenheit.
Slice the top portion off the garlic bulbs to expose the individual cloves.
Drizzle 2 tablespoons of olive oil over the exposed bulb tops.
Wrap the bulbs tightly in aluminum foil and place them on a baking sheet.
Roast the garlic for 45 minutes until the cloves are golden brown and soft.
While the garlic roasts, peel and cut the potatoes into 2-inch chunks.
Place the potatoes in a large pot and cover with cold water. Add 1 teaspoon of salt.
Bring the water to a boil and cook the potatoes for about 20-25 minutes, or until tender and easily pierced with a fork.
Drain the potatoes thoroughly and allow them to sit for a few minutes to remove excess moisture.
In a separate saucepan, melt the unsalted butter over medium heat, swirling occasionally, until it turns golden brown and nutty, about 3-4 minutes.
Off the heat, add the roasted garlic (squeezed into a small bowl) and stir in the brown butter.
Gradually add the heavy cream, stirring constantly to blend in the butter and garlic mixture.
Using a potato masher or ricer, work the potatoes into a smooth, creamy texture.
Add the seasoned brown butter and cream mixture, and fold it in with a wooden spoon until fully incorporated.
Stir in the remaining 1 teaspoon kosher salt and the freshly cracked black pepper.
Taste and adjust seasoning as needed.
For best results, cover the potatoes and refrigerate for up to 24 hours before reheating.