Preheat the oven to 375F.
Bring a large pot of water to a boil; add the potatoes. Boil approx 30 min or until tender when pieced easily with a knife.
Saute the oil, garlic and onion on the stove over medium heat. Add the mushrooms; cook 5-10 min.
Add the red wine and red wine vinegar; turn up heat to medium high and simmer.
Spread out the carrots on a cooking tray. Bake approx 30 min or until soft.
Mix together the broth in the 13x9 casserole dish: 2 c veggie broth, 1/4 c red wine vinegar, and 1/4 c tomato paste. Add the contents from the pan.
Cover with foil. Bake 40 min.
After potatoes cook, mash them and add butter, salt and chopped green onions.
Serve stew over mashed potatoes and enjoy.