Prepare Skinny Garlic Mashed Potatoes according to directions.
For the Vegetarian Shepherd's Pie: In a large sauté pan, heat the butter and oil. Add the mushrooms and ½ teaspoon salt, cook for 10 minutes, stirring occasionally.
Add the onion, carrots, parsley, thyme, ½ teaspoon salt and pepper and sauté 10 minutes.
Stir in garlic, cook for 30 seconds, then add the tomato paste, Worcestershire, remaining ¼ teaspoon salt and pepper.
Sprinkle vegetables with the flour, stir to coat and cook, scraping brown bits from the pan, 3-4 minutes.
Add the broth, peas and corn, cook, stirring often, until sauce has thickened (about 5 minutes).
To assemble the Mushroom Shepherd's Pie: Preheat broiler to high.
Transfer vegetables to an 8” x 11” casserole dish.
Spread mashed potatoes in an even layer over the vegetables, top with parmesan and broil 5 minutes, or until top is golden. Garnish with parsley.
