01 -
Turn on the oven and set it to 350°F. Coat a 9x13-inch baking dish with nonstick spray to prevent sticking.
02 -
Spread the shredded chicken evenly across the bottom of your prepared dish.
03 -
Place the ham strips over the chicken in an even layer so every bite has some.
04 -
Lay the Swiss cheese slices evenly on top of the ham, overlapping slightly to cover everything well.
05 -
In a medium saucepan over medium heat, melt 6 tablespoons of butter. Mix in Dijon mustard, lemon juice (if you're using it), garlic powder, salt, nutmeg (if using), and cayenne (if using). Stir to combine.
06 -
Whisk the flour into the melted butter a bit at a time until you’ve got a thick paste.
07 -
Gradually pour in the milk, about 1/4 cup at a time. Whisk well after every addition until smooth before adding more.
08 -
Once all the milk is incorporated, let it gently simmer for 4 minutes. Whisk regularly as it thickens.
09 -
Pour your finished sauce over the cheese layer. Use a spoon or spatula to spread it out evenly, making sure the corners aren’t missed.
10 -
In a small bowl, mix the softened butter with the breadcrumbs. Spread this over the top of the sauce as the final layer.
11 -
Put the dish in the oven and bake for 30-40 minutes, uncovered, until the topping is golden and crisp, and the sauce bubbles around the edges.
12 -
Pull the dish out of the oven and give it about 5 minutes to set. For an extra pop of color, sprinkle chopped parsley over the top (optional) and serve warm.