Shepherd's Pie - A Keeper!

It's Sunday and every week I try to make a nice homey dish for my fiance and me. I had leftover mashed potatoes and from being in England, I remember the best way to use up leftover mash is by making Shepherd's Pie. I used Emeril's recipe for the filling with a few adjustments:

Ingredients
1 1/2 tbsp olive oil
1 1/4 pound ground turkey 93/7
1/2 white onion chopped
1/4 red onion chopped
2 carrots, chopped
2 sticks celery chopped
Lawry's season salt
1 teaspoon fresh ground black peppercorn
4 ounces crimini mushrooms sliced
1 bay leaf
2 tablespoons all-purpose flour
4 tablespoon tomato sauce
1 1/2 cups chicken stock
2 tbsp Worcestershire sauce

1. Preheat oven to 400 degrees.
2. Heat oil in large pot over medium high heat. Add the ground turkey and cook until starting to brown, about 5 minutes.
3. Add the onions, carrots, celery, season salt and pepper and cook, stirring, for 5 minutes.
4. Add the mushrooms and bay leaf, and cook, stirring, until their liquid is almost all gone, about 2 minutes.
5. Add the tomato sauce and cook, stirring, until starting to color, about 1 to 2 minutes.
6. Add the flour and cook, stirring, for 1 minute.
7. Gradually add the stock and Worcestershire sauce, and bring to a boil. Cover and reduce heat to med-low to thicken sauce for about 10-15 minutes.
8. Spray Pam on a casserole dish. Add meat to dish then spread mashed potatos ontop. Sprinkle lightly with cheese then place in oven for 10 minutes.
9. Take off bake and turn broiler on High. Place under broiler for 5 minutes until lightly browned.
10. Let sit for a few minutes then serve. (Optional - sprinkle chives on top)

I meant to add frozen peas and green beens to this which I will do next time.
Also, I think adding garbanzo beans would be a great addition.