Cheesy Mashed Potato Casserole

Cheesy Mashed Potato Casserole with spinach is perfect for your holiday table. Mashed potatoes combined with P8armesan cheese, onions, garlic and spinach make this potato casserole extra delicious! 


  • 1 onion, diced (about 1½ cups)
  • 3 cloves garlic, minced
  • 4 tablespoons unsalted butter, room temperature, sliced into tablespoon portions
  • 11 ounces fresh spinach
  • 2 pounds Idaho® russet potatoes, peeled and quartered (5 medium potatoes)
  • 1½ cups heavy cream, warmed
  • 1 cup Parmesan cheese, grated + 2 tablespoons
  • 2 teaspoons kosher salt (+ salt for cooking water)
  • 1 teaspoon black pepper


  1. Preheat oven to 350°F.
  2. In a medium sauté pan, cook diced onions and garlic in 1 tablespoon butter over medium heat until onions are translucent, about 6 minutes. Set aside.
  3. Add spinach to the same pan (without rinsing) and cook until it is wilted and cooked down, about 4 minutes. Remove from pan and drain well. Squeeze out any excess liquid from the spinach. Set aside.
  4. Add potatoes to a large pot and cover with cold water. Add a big pinch of salt to the water. The water should taste a little salty.
  5. Bring to a boil over med-high heat and cook for 15–18 minutes, or until potatoes are easily pierced with a knife.
  6. While potatoes are cooking, heat cream over low heat in a small saucepot.
  7. Drain potatoes and push through a potato ricer while still hot.
  8. Over low heat, stir potatoes with a wooden spoon or heat-resistant spatula for one minute to let some of the moisture evaporate.
  9. Add warm cream, remaining butter, 1 cup Parmesan cheese, salt and pepper to potatoes. Using an electric mixer, beat potatoes 3–4 minutes, until thoroughly combined.
  10. Add spinach, garlic and onions and beat with an electric mixer until spinach is incorporated, 2–3 minutes.
  11. Placed mashed potato mixture in a 1.6L casserole dish, sprinkle the top with remaining 2 tablespoons Parmesan cheese and bake for 20 minutes until golden and bubbling.
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Yield: 8
Calories: 363
Sugar: 3g
Sodium: 883mg
Fat: 24g
Saturated Fat: 16g
Carbs: 26g
Fiber: 5g
Protein: 8g
Cholesterol: 83mg

Cheryl Bennett
Food Blogger
Pooks Pantry

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