Creamed Chicken and Biscuits

¼ cup butter ¼ cup plus 1 Tablespoon all-purpose flour 1 cup chicken broth 1 cup milk 1 egg yolk, beaten 2 cups cooked chicken, chopped 1 teaspoon salt 1 teaspoon pepper 1/2 cup drained canned carrots and 1/2 cup drained canned green beans (optional) 1 can refrigerated biscuits 1. Melt butter in a large pan over medium heat; add flour, blending well. 2. Gradually stir in broth, then milk. 3. Reduce heat to low; cook until thickened, about 2 to 4 minutes, stirring constantly. 4. Remove 1/4 cup milk mixture and gradually stir into egg yolk. 5. Return egg mixture to milk mixture. Add chicken, salt and pepper; heat through. 6. Serve creamed chicken over hot biscuits. Serves 4 to 6.