Preheat the oven to 350˚F.
Peel and cube the potatoes. Boil in water until cooked through, about 20 minutes. Drain and mash.
While the potatoes are cooking, heat a small skillet over medium heat and melt the butter. Add the onion and garlic and fry until fragrant and translucent, about 5-8 minutes. Turn the heat down if they start to color. Add the salt and pepper. Set aside until the potatoes are mashed.
Add the cooked onion and garlic to the mashed potatoes along with 1/2 cup of milk. Stir together until it is well combined and smooth. Add more milk as needed. Stir in the chives and add more salt and/or pepper if desired.
Place a large spoonful of potatoes in the base of your ramekin. Top with a piece of cheese and cover with more potatoes. Bake in the preheated oven for 15 minutes or until slightly golden on top. You may also see the cheese bubbling around the edges. Serve immediately.
I like to make these in individual cast iron mini pots but you could also use oven-proof ramekins. If you don’t have those, make this in a single oven-proof dish.
This is a great dish to make ahead. You can assemble everything and then wait to bake until ready.
Here’s a video on how to make this delicious recipe!