Flemish Potato and Leek Gratin with Gruyère
A comforting gratin featuring thinly sliced potatoes and leeks baked in a creamy cheese sauce, topped with a golden crust of Gruyère. This belgian-inspired vegetarian ready in about 75 minutes pairs peeled and thinly sliced potatoes, heavy cream, whole milk for a weeknight-friendly dinner that comes together with one pan and minimal cleanup. Each serving lands at about 380 calories and feeds 6, so it slots cleanly into a weekly meal plan and pairs well with a quick salad or grain on the side. Tap "Plan a meal with the AI" below to drop this recipe into your week and send the ingredients straight to Instacart. Nutrition values are approximate, calculated from USDA FoodData Central (fdc.nal.usda.gov) — verify against ingredient labels for any health-driven dietary plan.
Ingredients
- 1.5 lbs, peeled and thinly sliced potatoes
- 3 medium, white parts only, thinly sliced leeks
- 1 cup heavy cream
- 1/2 cup whole milk
- 1 cup grated Gruyère cheese
- 3 tbsp all-purpose flour
- 3 tbsp unsalted butter
- 1 tsp sea salt
- 1/2 tsp freshly ground black pepper
- 1 tsp chopped fresh thyme
Instructions
- Step 1: Preheat oven to 375°F (190°C). Grease a 9x13-inch baking dish with butter.
- Step 2: Melt 3 tbsp butter in a saucepan over medium heat. Whisk in 3 tbsp flour to form a roux, cook for 1 minute. Gradually whisk in 1 cup heavy cream and 1/2 cup milk until smooth.
- Step 3: Bring to a gentle simmer, stirring constantly, until thickened (about 5 minutes). Stir in 1 tsp sea salt, 1/2 tsp black pepper, and 1 tsp chopped thyme.
- Step 4: Layer half the sliced potatoes in the baking dish, then half the sliced leeks. Pour half the sauce over. Repeat layers with remaining potatoes, leeks, and sauce.
- Step 5: Sprinkle 1 cup grated Gruyère evenly over the top. Bake uncovered for 45-50 minutes until golden and bubbling around the edges, with potatoes tender when pierced with a knife.
Equipment for this recipe
Top-rated tools to make this recipe successfully.
Frequently asked questions
How long does Flemish Potato and Leek Gratin with Gruyère take to make?
Total time is about 75 minutes (25 min prep + 50 min cook). Most home cooks find this fits comfortably into a weeknight; double the batch on Sunday for two dinners.
How do I store leftover Flemish Potato and Leek Gratin with Gruyère?
Cool to room temperature within 2 hours, then store in an airtight container in the fridge for up to 4 days. Reheat covered in a 350°F oven for 10-12 minutes, or microwave at 70% power in 60-second bursts to keep heavy cream from drying out.
Can I substitute ingredients in Flemish Potato and Leek Gratin with Gruyère?
Yes — most ingredients in this recipe have flexible swaps. For oil, use any neutral high-smoke-point oil (avocado, grapeseed, refined coconut). For aromatics, dried herbs at ⅓ the volume of fresh work in a pinch. The full ingredient list is shoppable on Instacart so you can see substitutes in real time.
How do I scale Flemish Potato and Leek Gratin with Gruyère for a different number of people?
The recipe is written for 6 servings. Multiply each ingredient by (your serving target / 6). Cook time stays roughly the same up to 2x; for 3-4x batches, switch from a skillet to a sheet pan or stockpot so the food isn't crowded — overcrowding steams instead of browns.
What goes well with Flemish Potato and Leek Gratin with Gruyère?
Belgian vegetarian like this pair well with a simple grain (rice, couscous, or crusty bread), a quick salad with acid (lemon vinaigrette, pickled onions), and a pan sauce or yogurt-based dip. Tap "Plan a meal with the AI" to get specific side suggestions.
What others are saying
- ★★★★★
Doubled the garlic (as one does) and it was amazing.
- ★★★☆☆
Not bad. Would need significant modifications to make it a regular.
