Chicken Potpie Empanadas

Preheat the oven to 400 ° F. Melt the butter in a saucepan over medium-high heat. Add the onion and cook for 3 minutes. Add the flour and cook, stirring constantly, for 1 minute. While still stirring, slowly pour in the broth. Cook until thickened, about 3 minutes. Add the peas and carrots, chicken, salt and pepper. Remove from heat. Cut each cake in half to form 4 semicircles. Spoon the chicken mixture over the bottom half of each semicircle, leaving a 1/2-inch thick rim. Use your fingers to moisten the edges with water. Wrap each cake on top of the chicken to form a quarter circle. Tap to seal. Make three 1-inch-thick incisions in each top cake. Transfer to a baking sheet. Bake until golden brown, 15 to 18 minutes.