To a large soup/stock pot, over medium heat, add the onions and olive oil.
Sauté the onions for 2 to 3 minutes until they become soft.
Add the mushrooms and stir into the onions; sauté until the mushroom release their moisture and become browned; about 10 minutes will do.
Next, add the chopped carrots, celery, salt and pepper; stir to combine and cook for 5 minutes.
Add the garlic and continue cooking for 2 minutes.
Next, add the vegetable stock, potatoes, tomato paste, oregano, basil, paprika, and rosemary; stir to combine.
Cover the pot with a lid and allow to cook for 25 minutes; stirring occasionally; check to see that the potatoes and carrots are fork tender; if not, allow five more minutes of cooking time.
If they are tender, add the frozen peas; stir into the stew and continue to cook for 2 to 3 minutes.
Scoop out two cups of the stew – try to get an even amount of vegetables and broth.
Puree in a blender until completely smooth.
Return the puree to the pot and stir into the stew.
Add the chopped parsley; stir and turn off the heat.
Place the lid back on the pot and allow the stew to sit for five minutes.
Stir again and serve immediately.