Cheesy Potato Gratin
Inspired by techniques from Serious Eats and NYT Cooking.
Thinly sliced potatoes are simmered in a garlic- and thyme-infused cream, layered with Gruyère and Parmesan, then baked until bubbling and deep golden on top.
Always check the labels of the products you use.
Method
- 1
Infuse the cream. Bring the cream, milk, garlic, shallots, thyme, nutmeg, salt and pepper to the boil in a saucepan, then take off the heat, cover and leave to steep for 30-60 minutes. This slow infusion draws flavour from the garlic, shallot and thyme into the liquid without needing to simmer it down.
- 2
Strain and slice. Return the liquid to the boil, then strain it through a fine sieve into a large heatproof bowl, discarding the solids. Slice the potatoes 1.5-2 mm thick straight into the hot liquid, stirring so every slice is coated; skip rinsing them, since the starch on their surface is what thickens the sauce as it bakes.
- 3
Preheat and mix cheeses. Preheat the oven to 180°C (160°C fan) at least 20 minutes ahead, and butter the baking dish. Mix the grated Gruyère and Parmesan together, keeping the final third aside for the top layer.
- 4
Layer the gratin. Layer the potato slices in the dish, scattering cheese between each layer and reserving the last portion for the top. Pour over the remaining infused liquid until it just reaches the top layer of potatoes. Building it in layers lets the cheese melt evenly through the gratin instead of pooling at the base.
- 5
Bake covered, then open. Cover with foil and bake on a tray for 45 minutes, then remove the foil, scatter over the remaining cheese and bake for a further 30-40 minutes. It's ready when a knife slides through with no resistance and the top is deep golden; the foil traps steam early on to cook the potatoes through before the top is left bare to brown.
- 6
Rest before cutting. Let the gratin rest for 15 minutes before cutting into it. As it cools slightly, the starchy cream firms up and sets, so the layers hold together on the plate instead of slipping apart.
Storage
Keep covered in the fridge for up to 3 days. Reheat portions in a low oven or microwave until piping hot throughout (74°C); this dish freezes well for up to 2 months, thawed overnight in the fridge before reheating. Cool leftovers in a shallow container and refrigerate within 2 hours (within 1 hour on a day above 32°C).
Equipment
- medium saucepan
- fine sieve
- large heatproof bowl
- mandoline or very sharp knife
- 2-litre baking dish (about 20 x 30 cm)
- baking tray
- foil
Nutrition per serving (estimated values)
| Per serving | Amount |
|---|---|
| Energy | 453 kcal |
| Protein | 16.4 g |
| Carbohydrate | 35.7 g |
| of which sugars | 7.2 g |
| of which free sugars | 0 g |
| Fat | 27.9 g |
| of which saturates | 17.2 g |
| Fibre | 3.7 g |
| Salt | 1.56 g |
Protein per 100 kcal
3.6 g High Protein needs ≥ 10 g
Calculated from USDA FoodData Central ingredient values
