Directions

  1. Preheat oven to 350°F. Spray a 13 x 9-inch baking dish with nonstick cooking spray. Heat a large saucepot of water to a boil over high heat; add potatoes and simmer 10 minutes or until fork-tender.
  2. Beat potatoes, milk and 1 teaspoon salt in a large bowl with mixer on medium speed 3 minutes or until smooth. Makes about 6 cups.
  3. Heat oil in a large saucepot over medium-high heat. Add celery, carrots, onion and cauliflower; cook 7 minutes or until vegetables are almost tender, stirring occasionally. Add mushrooms; cook 9 minutes or until mushrooms are tender, stirring occasionally. Add garlic; cook 2 minutes, stirring occasionally. Add tomato paste; cook 2 minutes, stirring frequently. Reserve 6 tablespoons stock in a small bowl; stir remaining stock, peas, thyme, pepper and remaining 2 teaspoons salt into saucepot. Heat to a simmer, scraping browned bits from bottom of saucepot. Whisk cornstarch into reserved stock until smooth; stir into saucepot. Makes about 9 cups.
  4. Transfer vegetable mixture to prepared dish; top with potato mixture. Bake 35 minutes or until top is lightly browned; let stand 10 minutes. Makes about 14 cups.