Chicken and Mushroom Crêpes with Mornay Sauce

Prepare the crêpe batter: In a large bowl, whisk together 1 cup flour, eggs, 1 cup milk, 1/4 teaspoon salt, and 2 tablespoons melted butter until smooth. Let the batter rest for 15 minutes.

Cook the crêpes: Heat a lightly buttered 8-inch non-stick skillet over medium heat. Pour about 1/4 cup of batter into the skillet, swirling to coat the bottom evenly. Cook for 1-2 minutes until the edges are golden, then flip and cook for another 30-60 seconds. Repeat with remaining batter to make 8 crêpes.

Prepare the filling: In a large skillet, melt 2 tablespoons butter over medium-high heat. Add the cubed chicken and cook until browned and cooked through, about 5-7 minutes. Add the sliced mushrooms and cook until softened, about 5 minutes. Stir in the chicken broth and bring to a simmer, then remove from heat.

Make the Mornay sauce: In a medium saucepan, melt 2 tablespoons butter over medium heat. Whisk in 2 tablespoons flour and cook for 1 minute, stirring constantly, to create a roux. Gradually whisk in 1 1/2 cups milk until smooth. Bring to a gentle simmer, stirring, until the sauce thickens, about 5-7 minutes. Stir in nutmeg, Gruyère cheese, and Parmesan cheese until melted and smooth. Season with 1/4 teaspoon salt and 1/4 teaspoon black pepper.

Assemble the crêpes: Preheat oven to 375°F (190°C). Lay a crêpe flat and spoon about 1/4 cup of the chicken and mushroom filling onto one half. Fold the crêpe in half, then in half again to form a triangle. Repeat with the remaining crêpes and filling.

Bake the crêpes: Arrange the filled crêpes in a single layer in a baking dish. Pour the Mornay sauce evenly over the crêpes. Bake for 15-20 minutes, or until the sauce is bubbly and lightly golden.

Serve immediately, garnished with fresh parsley if desired.