Place the diced peeled potatoes in a large saucepan, cover with water, bring to a boil, and simmer for 15 minutes or until soft. Drain the water and roughly mash. Add plant-based milk, vegan butter, salt, and pepper, all to taste, and continue mashing until completely smooth. Set aside.
In a medium bowl, add the dried mushrooms, bouillon cube, and water. Let the mushrooms soak for 8 minutes, and mix to dissolve the vegetable stock.
Preheat the oven at 430 degrees F.
Heat a large frying pan with the olive oil on medium heat. Add the carrots, onion, basil, oregano, rosemary, and thyme. Stir and cook until lightly soft.
Add the tomato puree to the frying pan and stir. Take your soaking mushrooms and pour the liquid into the frying pan, holding back the mushrooms. Roughly chop the mushrooms before adding them to the pan as well. Add the chopped sundried tomatoes and lentils, and simmer until thickened.
Once the cottage pie mixture is ready, spread it evenly in a casserole dish. Top with the mashed potatoes and sprinkle generously with nutritional yeast. Cook in the oven for 10 minutes or until the surface is golden. Garnish with parsley or chives and enjoy!