Gather all ingredients before starting the recipe.
Pre heat oven to 375°℉
Cube 1-2 cups left over roast beef or lamb and pulse in a food processor until finely ground.
Heat 1-2 tbsp olive oil in a large frying pan over medium high heat, 1/2 large Spanish onion chopped and sauté until translucent, 5 -7 minutes.
Add ground roast and 2 tbsp Beef Bovril, stir to combine and cook for 2-3 minutes to heat through. Season with black pepper to taste.
Sprinkle 1-2 tbsp all-purpose flour over mixture and stir to combine, cook for a further 2-3 minutes
Add 3/4 cup beef broth , bring to boil the reduce heat to medium and simmer for about 15 minutes or until the mixture becomes thick.
Ladle ground roast mixture into an oven proof casserole dish, (or several smaller ones) top with 1 cup canned or frozen corn and 1 cup canned or frozen peas and finally top with 1-2 cups left over mashed potatoes or store-bought mashed potatoes.
Place in a pre-heated 375° ℉ for 30-40 minutes, or until completely heated through.