Melt butter in a medium size saucepan. Add flour and cook over medium heat, about five minutes. Add chicken broth and heat until mixture just begins to boil. Reduce heat; add chicken, potato and mixed vegetables until heated through. Pour into a 2-quart casserole dish. Combine Bisquick, milk, and egg; pour over chicken mixture.
Bake at 400°F for 30 minutes or until golden.
Serving Size: 4