Heat the oven to 425 degrees.
Rinse, drain and cook the lentils according to package directions, for about 40 minutes.
Wash the potatoes. Heat a large pot of water to boil, and then add the potatoes. Simmer for about 20 minutes, or until the potatoes are fork tender.
Dice the cauliflower, and roast at 425 for 20 minutes, stirring once.
Shred the carrots and set aside.
Remove the lentils from heat, along with the potatoes and cauliflower.
Put the potatoes and cauliflower in a large bowl and mash with a potato masher or the back of a spoon. Add the lentils, shredded carrots, spices, tahini, and cilantro, and stir together well.
Make the sauce: add the tahini, water, lemon juice, nutritional yeast, olive oil, curry, garlic powder, mustard and salt to a food processor, and process for a minute, until all ingredients are well blended.
Heat 1 tbsp. olive oil in a large frying pan on medium high. Form the cauli-potato mixture into patties, and add to the pan, cooking for about 5 minutes on each side, until lightly browned.
Serve on buns along with the tahini mustard sauce and your favorite toppings.