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Vegetarian Portobello Pot Roast Recipe
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4.24 from 63 votes

Vegetarian Portobello Pot Roast

This vegetarian Portobello Pot Roast recipe is quick and simple to prep, easy to cook in the Instant Pot or slow cooker, and it's full of the classic savory flavors we all love!
Prep Time10 minutes
Cook Time4 hours
Total Time4 hours 10 minutes
Course: Main Course
Cuisine: Italian
Keyword: dairy free, vegan, vegetarian
Servings: 6 -8 servings

Ingredients

  • 1.25 pounds Yukon gold potatoes cut into bite-sized pieces
  • 1 pound baby bella mushrooms (if they are large cut them in half)
  • 2 large carrots peeled and cut into bite-sized pieces
  • 2 cups frozen pearl onions*
  • 4 cloves garlic peeled and minced
  • 3 sprigs fresh thyme
  • 3 cups vegetable stock divided
  • 1/2 cup dry red or white wine
  • 3 tablespoons tomato paste
  • 2 tablespoons vegetarian Worcestershire sauce*
  • 2 tablespoons cornstarch
  • Kosher salt and freshly-cracked black pepper
  • optional garnish: finely-chopped fresh parsley

Instructions

Slow Cooker Method:

  • Add potatoes, mushrooms, carrots, onions, garlic, thyme, 2.5 cups vegetable stock, wine, tomato paste and worcestershire together in the bowl of a crock pot, and gently toss to combine.  Cook on low for 6-8 hours, or on high for 3-4 hours, until the potatoes and carrots are tender.
  • In a separate bowl, whisk together the remaining 1/2 cup vegetable stock and cornstarch until combined.  Add to the roast mixture, and gently toss to combine.  Continue to cook for 1-3 minutes, until the sauce thickens up a bit.
  • Serve immediately, garnished with fresh parsley if desired.

Instant Pot Method:

  • Add potatoes, mushrooms, carrots, onions, garlic, thyme, 2.5 cups vegetable stock, wine, tomato paste and worcestershire together in the bowl of a pressure cooker, and gently toss to combine.  Close lid securely and set vent to “Sealing”.
  • Press “Manual”, then press “Pressure” until the light on “High Pressure” lights up, then adjust the up/down arrows until time reads 20 minutes.  Cook.  Then let the pressure release naturally, about 15 minutes.  Carefully turn the vent to “Venting”, just to release any extra pressure that might still be in there.  Remove the lid.
  • In a separate bowl, whisk together the remaining 1/2 cup vegetable stock and cornstarch until combined.  Add to the roast mixture, and gently toss to combine.  Continue to cook for 1-3 minutes, until the sauce thickens up a bit.
  • Serve immediately, garnished with fresh parsley if desired.

Notes

Onions: Feel free to sub in sliced white onions, if pearl onions are not available.
Worcestershire: If making this recipe vegetarian, be sure to use vegan Worcestershire sauce.
***Cook time listed above is for a slow cooker set on "high".