To prepare a vegetarian shepherds pie beans and grains recipe, you will first need to gather your ingredients. You will need: 1 pound chuck roast, 2 lbs ground sirloin, 1/2 cup chopped scallions, 1 cup diced celery, and 2 tablespoons kosher salt. Preheat the oven to 375 degrees F (190 degrees C) and prepare your oven rack to line the bottom of the pie dish with foil. Place the roast in the preheated oven and roast for 1 hour and 15 minutes or until the internal temperature reaches 160 degrees Fahrenheit (65 degrees Celsius).