- Melt the butter. In a medium saucepan over medium heat, melt the butter. Once melted, add the flour and whisk continuously to form a roux. Cook the roux for about 1-2 minutes, until it becomes slightly golden and fragrant. This removes the raw taste of the flour.
- Add the milk. Slowly pour in the milk while continuing to whisk, ensuring there are no lumps. Bring the mixture to a simmer, whisking frequently until it thickens into a creamy sauce, about 5-7 minutes.
- Season the sauce. Stir in the Dijon mustard (if using), nutmeg, and season with salt and pepper to taste. Once the sauce has thickened, remove from heat and set aside.
Stage 2: Assembling the Gratin
- Prepare the eggs. Peel the hard-boiled eggs and slice them in half lengthwise. Place the egg halves, cut side up, in a greased baking dish.
- Pour the béchamel sauce. Pour the prepared béchamel sauce evenly over the egg halves, making sure each egg is well-covered.
- Add the cheese and breadcrumbs. Sprinkle the grated Gruyère cheese over the top of the sauce and eggs. Then, sprinkle the Parmesan cheese and breadcrumbs on top for an added crispy, golden texture when baked.
Stage 3: Baking the Gratin
- Preheat the oven. Preheat your oven to 375°F (190°C).
- Bake the gratin. Place the baking dish in the oven and bake for 15-20 minutes, or until the top is golden brown and bubbly. If you like an extra crispy top, you can broil it for an additional 2-3 minutes at the end, but keep a close eye on it to prevent burning.
Stage 4: Serving
- Garnish and serve. Once the gratin is out of the oven, sprinkle freshly chopped parsley over the top for color and a touch of freshness. Serve immediately while it’s still hot and bubbly.
Tips for the Best Hard-Boiled Egg Gratin:
- Use fresh eggs: The fresher the eggs, the easier they are to peel. If you have time, use slightly older eggs for hard-boiling, as they tend to peel more easily.
- Make it ahead: You can prepare the béchamel sauce and assemble the gratin in advance, then bake just before serving.
- Customize the topping: Feel free to swap in different cheeses based on your preference. Gruyère, cheddar, and mozzarella all melt beautifully and add richness to the dish.
- Add extra flavor: For a deeper flavor, you can add a pinch of cayenne pepper, garlic powder, or even sautéed mushrooms to the béchamel sauce.
Final Thoughts:
This Hard-Boiled Egg Gratin with Béchamel Sauce is a rich, comforting dish that takes the humble hard-boiled egg to the next level. The creamy béchamel sauce, melted cheese, and crispy topping create a dish that’s perfect for brunch, a side dish, or even a light dinner. It’s easy to make, yet impressive enough for guests, making it a versatile addition to any meal. Enjoy!