1. Preheat oven to 350° F. Prepare a 9 x 13 baking dish with cooking spray. Add turkey to dish; spread out evenly. Chop ham into 1-inch chunks and spread over top of turkey. Sprinkle with Swiss cheese. Set aside.
2. Prepare sauce by melting butter over medium heat in saucepan. Once melted, lower heat. Stir in the flour until a yellow paste forms. Slowly begin whisking in the broth a 1/2 cup at a time until incorporated and sauce begins to thicken. After all liquid is added, add salt and pepper. Cook on medium heat for 10 minutes, whisking occasionally. Add lemon juice; stir to combine. Taste for seasoning. Add more salt or pepper, if necessary. Turn off the heat and let cool to room temperature. 
3. When sauce has cooled, pour over the casserole. In large bowl, stir together breadcrumbs, parmesan, olive oil and parsley. Spread over the top of casserole. Bake uncovered for 30 to 45 minutes until heated through and top is golden-brown. Remove from oven; let cool for 10 minutes before serving.

Calories: 506, Fat: 28 g (14 g Saturated Fat), Cholesterol: 147 mg, Sodium: 1172 mg, Carbohydrates: 10 g, Fiber: 1 g, Protein: 52 g.