60g butter
30g all-purpose flour
475ml half-and-half
0.5 teaspoon salt
0.25 teaspoon ground black pepper
0.25 teaspoon garlic powder
0.25 teaspoon dry mustard
100g shredded Gruyère cheese
8 hard-boiled eggs, peeled and halved
50g freshly grated Parmesan cheese
Step 1
Preheat the oven to 175 degrees C (350 degrees F). Grease a 23cm square baking dish with butter.
Step 2
In a saucepan over medium-low heat, melt the butter. Add the flour and whisk until smooth, about 2-3 minutes. Gradually pour in the half-and-half, whisking until the sauce thickens and becomes smooth, approximately 5 minutes. Season the sauce with salt, pepper, garlic powder, and dry mustard. Stir in the Gruyère cheese until melted and smooth.
Step 3
Arrange the hard-boiled eggs, cut-side down, in the prepared baking dish. Pour the creamy sauce over the eggs and sprinkle with Parmesan cheese.
Step 4
Bake in the preheated oven until the casserole is bubbly and golden brown, about 20-25 minutes.