Cheesy, creamy mashed potatoes topped with garlic parmesan potato gratin – this truly is the ultimate side dish!

Ingredients

For the Mashed Potatoes

• 1.5kg / 3.3lb baking potatoes, peeled and diced
• 1 Tablespoon + 1 teaspoon salt, or to taste
• 6 Tablespoons / 90g butter, at room temperature
• 160ml / 2/3 cup cream, at room temperature
• 150g / 1 1/2 cups cheddar cheese, grated
• 1/4 teaspoon black pepper, or to taste

For the Potato Gratin Topping

• 750g / 1.6lb baking potatoes, peeled and thinly sliced into half moons (about 1/8” thick)
• 2 Tablespoons / 30g butter, melted
• 1 large clove of garlic, finely grated or minced
• 1/4 – 1/2 teaspoon salt, or to taste
• 1/8 – 1/4 teaspoon black pepper, or to taste
• 40g / 1.4 oz Parmesan cheese, grated
• Fresh chives, finely diced, for garnish

Procedure

1. Make the Mashed Potatoes: Place the peeled and diced potatoes in a large pot of cold water. Add 1 tbsp salt, then bring to a boil over high heat.
2. Cook the potatoes until knife-tender (soft but not falling apart). Drain and set aside for 1 minute.
3. Return the pot to low heat and add the butter and cream, stirring to melt.
4. Add the drained potatoes to the pot and mash until smooth. Stir in the cheddar cheese until melted and season with salt and pepper to taste.
5. Spoon the mashed potatoes into a 25cm x 17cm / 10” x 6.5” baking dish (or similar size) and level off with a spoon.
6. Prepare the Potato Gratin Topping: Preheat  the oven to 200C/400F.
7. In a large mixing bowl, combine the melted butter, garlic, salt, and pepper. Toss the sliced potatoes in the mixture, then add half of the Parmesan and toss again until well coated.
8. Layer the potato slices cut-side down on top of the mashed potatoes in three rows at a slight angle.
9. Bake the Casserole: Cover the dish with foil and bake for 20 minutes.
10. Remove the foil, sprinkle the remaining Parmesan over the top, and bake uncovered for another 40 minutes, or until the top is golden and the potatoes are tender.
11. Rest and Serve: Allow the casserole to rest for 15–20 minutes before serving. This will help the layers set and finish cooking.
12. Garnish with fresh chives, then serve and enjoy!

Cook’s Notes

• Potatoes: Use floury or baking potatoes like Russet for the best texture.
• Parmesan: Use fresh “dusty” Parmesan for the best distribution.
• Texture: After 1 hour, the top should be knife-tender. If not, cover with foil and bake a bit longer.