Leftover Mashed Potato Cheesy Vegetarian Hash - Make the best use of your leftover mashed potatoes by adding crispy cheese, roasted veggies, and a fried egg! This is my favorite hot breakfast ever!

Leftover Mashed Potato Cheesy Vegetarian Hash

This cheesy hash is the best way to use up leftover mashed potatoes, especially when topped with a runny fried egg!
Course Breakfast
Cuisine American
Prep Time 5 minutes
Cook Time 15 minutes
Total Time 20 minutes
Servings 1
Calories 225kcal
Author Lindsay Moe


  • 1 tablespoon olive oil
  • 1 small onion
  • Coarse kosher salt and freshly ground black pepper
  • 1 handful of leafy greens such as spinach
  • About 1 cup leftover mashed potatoes
  • 1 handful cheese such as gruyere, mozzarella, feta, or Monterey jack
  • 1 fried egg optional


  • Heat olive oil in a medium pan over medium heat. Add the onion and season with salt and pepper. Cook, stirring frequently, until the onion is beginning to soften, 5-7 minutes.
  • Add a handful of leafy greens and stir until wilted, usually less than one minute.
  • Add the mashed potatoes and break up into an even layer if cold. Allow to cook until heated through, scraping the bottom of the pan and flipping every few minutes.
  • Add the cheese and continue to cook, breaking up, scraping, and flipping the potatoes every few minutes, until the potatoes and cheese have formed a brown crust throughout. Transfer to a plate, season with salt and pepper and top with a fried egg if desired.


Ideas to customize this leftover mashed potato cheesy vegetarian hash:
  • Use any vegetables you have on hand such as roasted garlic, cooked broccoli, cauliflower, peppers, or kale
  • Use any cheese you like such as cheddar, gorgonzola, or an Italian blend
  • Mix and match for different flavor profiles. Go Mexican with cheddar, peppers, and a bit of salsa, or Greek with feta, roasted peppers, spinach, and olives.
  • Serve alongside your favorite eggs
  • Serve with sausage links or add crumbled bacon for a non-vegetarian option
  • Top with a drizzle of sriracha or a few dashes of hot sauce


Calories: 225kcal | Carbohydrates: 7g | Protein: 7g | Fat: 18g | Saturated Fat: 3g | Cholesterol: 164mg | Sodium: 95mg | Potassium: 330mg | Fiber: 1g | Sugar: 3g | Vitamin A: 3050IU | Vitamin C: 13.6mg | Calcium: 70mg | Iron: 1.6mg