Preheat your oven to 375°F (190°C).
Lightly butter a 9x13-inch baking dish.
In a small saucepan, heat the cream and garlic over medium heat until steaming. Remove from heat.
Layer half of the potato slices in the baking dish. Season with salt and pepper.
Sprinkle half of the Gruyère and cheddar over the potatoes.
Pour half of the warm cream mixture evenly over the layers.
Repeat with remaining potatoes, seasoning, cheese, and cream.
Cover with foil and bake for 35 minutes.
Remove foil and bake for another 20–25 minutes, until golden and bubbly.
Let stand 10 minutes before serving. Garnish with chopped chives.