Mushroom Shepard's Pie

I know what you thinking: mushrooms don't get shepherded! Well they do when I decide to give a recipe a make-over. You might notice that the above filling looks very familiar. That is because I re-did the Phyllo Topped Potpie which was posted only yesterday. While the Phyllo Topped Potpie was caloricially good, I found it too sweet. Thinking this sweetness was caused by the phyllo topping I decided to re-do it with a mashed potato topping. To keep the calories down I made the topping out of boxed mashed potatoes and I left out the butter and used low fat milk.

1 (8 ounce) package white mushrooms, sliced

2 large portobella mushrooms, cubed

2 carrots, diced

1 (16 ounce) package frozen corn, thawed

1 (16 ounce) package frozen Lima beans, thawed

1 tablespoon all-purpose flour

2 teaspoons dry mustard

1 teaspoon dried thyme

1 teaspoon dried parsley

1/2 teaspoon dried dill

1/2 cup vegetable broth

2 tablespoons fat free half-n-half

1 teaspoon prepared Dijon mustard

1 teaspoon black pepper

1/2 teaspoon kosher salt

2 cups prepared instant mashed potatoes (prepared without the butter and with low-fat milk)

1/4 cup of shredded reduced fat cheddar cheese

1. Move the oven rack to the lower middle position and preheat the oven to 350°.
2. Spray a large skillet with cooking spray and heat over medium heat. Add both kinds of mushrooms and the diced carrots; cook until softened, about 8 minutes. Stir in the corn and lima beans. Sprinkle the flour, dry mustard, thyme, parsley, and dill over the mushroom mixture and stirring constantly until well incorporated, about 1 minute. Slowly stir in the broth, half-n-half, Dijon mustard, pepper, and kosher salt; bring to a boil. Reduce the heat to a simmer and allow to cook stirring occasionally until the sauce thickens, about 5 minutes.
3. Transfer the mushrooms mixture into a 2 quart baking dish. Top with mashed potatoes and cheese. Bake until the the cheese is melted and the mixture is bubbling.