Preheat the oven to 375℉.
Slice the tops off the tomatoes. Reserve the tops.
Score the flesh of the tomato with the tip of a sharp knife. Then, with a small spoon scoop out the flesh into bowl. Be careful not to pierce the skin.
Place the hollowed out tomatoes in a baking dish. Sprinkle the inside of each with a pinch of salt and pepper. Set aside while you prepare the filling.
Place the scooped out tomato into a food processor and process until pureed. Set aside.
Heat a large pan over medium heat. Add two tablespoons of olive oil, and saute the onions and garlic until soft and translucent.
Add the rice, tomato pulp and ½ cup of water to the pan. Lower the heat to a simmer, cover and cook for 10-15 minutes until the rice is approximately half way cooked.
Remove the pan from the heat. Add the herbs, nutritional yeast, and salt & pepper to taste.
Stuff each of the tomatoes about ¾ full with the rice mixture.
Place the tops back on each of the vegetables.
Cut the Yukon Golds into large wedges. arrange the potatoes around the tomatoes.
Mix the tomato paste with ½ cup of water, and pour over the vegetables in the baking dish.
Drizzle everything with the remaining olive oil.
Place the baking dish in the oven and bake for about 1 and a half hours, or until the rice and potatoes are cooked through.
Let the stuffed tomatoes cool for at least ½ hour. Serve warm, or at room temperature.