Add grapeseed oil to a large pot over medium heat. Once hot, add onion, carrot, and 1/2 tsp sea salt and cook, stirring often until vegetables are well browned, about 10-12 minutes.
Add mushrooms, increase heat to medium-high, stirring continuously until mushroom liquid evaporates, about 10 to 12 minutes.
Add garlic, tomato paste, thyme, and smoked paprika and cook until fragrant, about 30 seconds. scraping up any browned bits. Stir in veggie broth, water, potatoes, and bay leaf; bring to simmer.
Reduce heat to medium-low, partially cover, and cook until stew is thickened and vegetables are tender, 30 to 35 minutes. When complete, discard bay leaf and stir in parsley (or greens of your choice) and lemon juice. Season with sea salt and black pepper to taste, and enjoy.