Cook potatoes in boiling water until tender. While potatoes are cooking, in a frying pan, heat olive oil. Add in onions and garlic. Cook for 5 minutes. Add in the rest of the vegetables and cook for another 10-15 minutes. Add in lentils, water/stock and flour. Cook for another 5 minutes until the mixture thickens. Drain potatoes, return them to the pot and add in avocado oil, milk and cheese. Mash potatoes using a potato masher until smooth. Preheat oven to 180C and grease a baking dish. Transfer the vegetable mixture into the prepared baking dish and top with potato mash. Bake for 20 minutes or until golden. Serve warm garnished with fresh parsley and enjoy.