Sweet potato gratin

A soft, lightly sweet gratin of thinly sliced sweet potato: a colourful alternative to the classic gratin dauphinois, with more fibre. Comforting and easy, it goes with meat or fish, or can be enjoyed on its own with a salad for a vegetarian dinner.

Preparation: 15 min  |  Cooking: 45 min  |  Servings: 4  |  Difficulty: Easy

Calculated per serving from Anses Ciqual 2025 values for each ingredient, based on the quantities in the list. Household measures (spoonfuls, pieces) use average weights. 219 kcal · 6 g protein · 36 g carbohydrate · 4 g fat

Ingredients

• 4 sweet potatoes
• 200 ml milk or light cream
• 60 g grated cheese
• 2 cloves of garlic
• nutmeg, thyme, salt, pepper

Method

1. Preheat the oven to 180°C (160°C fan). Peel the sweet potatoes and cut into thin slices (a mandoline is ideal).
2. Layer them in a dish with the garlic, salt, pepper, nutmeg and thyme.
3. Pour in enough milk to come level with the top and sprinkle with grated cheese.
4. Bake for 40 to 45 minutes, until the sweet potatoes are tender and the top is golden.

Nutritional benefits

Sweet potato is richer in fibre and beta-carotene (provitamin A) than white potato, with a more moderate glycaemic index, which makes it a nutritionally better base for a gratin. Using milk or light cream rather than double cream makes the dish noticeably lighter. The cheese, in a reasonable amount, provides the golden topping and a little calcium. A comforting, colourful side that is better balanced than the traditional gratin.

Variations and substitutions

• Dairy-free: plant-based milk and nutritional yeast.
• Mixed: sweet potato with potato or with squash.
• Higher in protein: add lentils or diced smoked tofu.
• With spices: curry, smoked paprika, rosemary.

Storage and making ahead

This gratin keeps for 3 days in the fridge and can be reheated in the oven. It also freezes in portions. Slice the sweet potatoes thinly for even cooking and a really soft gratin.

💡 Good to know

A mandoline makes the job much quicker and gives even slices that cook uniformly. Nutmeg and thyme bring out the natural sweetness of the sweet potato.

See also

Discover more vegetarian recipes · healthy & balanced recipes · gluten-free recipes.

Ingredients in this recipe: sweet potatoes · milk · cream · cheese · garlic.

You might also like these recipes: Vanilla chia pudding · Buckwheat galettes with ham, cheese and egg · Quinoa tabbouleh.