Step 1: Melt 2 tablespoons butter in a large skillet over high heat.
Step 2: Add 8 ounces sliced mushrooms; cook, stirring, until lightly browned, about 5 minutes. Sprinkle with 1 tablespoon flour. Cook, stirring, 1 minute. Stir in the finely grated zest and the juice of 1 small lemon, scraping up browned bits. Stir in 1 cup chicken broth, 2 cups cooked chicken pieces, 2 tablespoons capers, chopped, 1/2 teaspoon salt and pepper to taste. Reduce heat; simmer, 5 minutes. Stir in 2 tablespoons whipping cream.
Step 3: Serve over rice, sprinkle with chopped flat-leaf parsley.