Add oil or vegan butter to a large, heavy-bottomed stockpot or Dutch oven over medium-high heat. Add in protein of choice and sear until browned, about 3-5 minutes.
Add in onions and mushrooms and sauté for 5-8 minutes, until mushrooms have shed most of their excess moisture and onions are slightly browned.
Stir in minced garlic, then sprinkle with all-purpose flour and stir to coat. Continue to cook, stirring often, for 2-3 minutes.
Deglaze the pot with red wine, scraping up any fond that might be sticking to the bottom of your pan.
Add in the broth, tomato paste, carrots, celery, and cubed potatoes. Add in fresh herbs, bay leaves, and black pepper. Stir to combine.
Bring the mixture to a boil, then reduce heat to low/medium-low to establish a gentle simmer. Cover and simmer for 1 hour.
Add in frozen peas. Whisk together cornstarch slurry and stir it into the stew. Allow the stew to simmer until thickened to preference.
Discard bay leaves and herb stalks. Taste and adjust salt to preference.
This stew is delicious served over buttered noodles, steamed rice, mashed potatoes, or with a slice of hearty bread.