Gruyère and Mushroom Gratin
A baked casserole of creamy Gruyère, earthy mushrooms, and a touch of thyme, inspired by Brussels' rustic culinary traditions. This belgian-inspired quick meals ready in about 55 minutes pairs grated Gruyère cheese, sliced button mushrooms, finely chopped shallots for a weeknight-friendly dinner that comes together with one pan and minimal cleanup. Each serving lands at about 500 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 cup, grated Gruyère cheese
- 12 oz, sliced button mushrooms
- 2, finely chopped shallots
- 1 tsp, fresh or 1/2 tsp dried thyme
- 2 tbsp butter
- 2 tbsp flour
- 1 cup milk
- 1/2 tsp salt
- 1/4 tsp black pepper
Instructions
- Step 1: Melt 2 tbsp butter in a large skillet over medium heat. Add 2 chopped shallots and sauté for 2 minutes until fragrant.
- Step 2: Add 12 oz sliced button mushrooms and cook for 8-10 minutes until tender, stirring occasionally.
- Step 3: Stir in 1 tsp thyme and season with 1/2 tsp salt and 1/4 tsp black pepper. Remove from heat and set aside.
- Step 4: In a mixing bowl, combine 1 cup grated Gruyère cheese, 2 tbsp flour, 1 cup milk, and 1 tsp thyme. Mix until smooth.
- Step 5: Layer the mushroom mixture in a greased baking dish, then spread the cheese-milk mixture on top. Bake at 375°F (190°C) for 20-25 minutes until golden and bubbly.
Equipment for this recipe
Top-rated tools to make this recipe successfully.
Frequently asked questions
How long does Gruyère and Mushroom Gratin take to make?
Total time is about 55 minutes (25 min prep + 30 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 Gruyère and Mushroom Gratin?
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 grated gruyère cheese from drying out.
Can I substitute ingredients in Gruyère and Mushroom Gratin?
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 Gruyère and Mushroom Gratin 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 Gruyère and Mushroom Gratin?
Belgian quick meals 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
- ★★★★☆
Nice recipe! Presentation was beautiful. Flavor was good, not great.
- ★★★★☆
Almost perfect — just needed a squeeze of lemon at the end.
- ★★★★☆
Good flavors but the sauce was a bit thin. I'd reduce it longer.
