In a large mixing bowl or in the bowl of a stand mixer, place the sugar, yeast, and warm water and wait about five minutes to ensure the yeast froths.
Add the tofu mixture and then add two cups of flour, salt, and oil and mix.
Add the remaining flour, half a cup at a time, until the dough comes together but is still fairly sticky and soft. I needed about 3 1/2 cups of flour, but the amount you need could vary based on temperatures and humidity where you are.
Place the dough in an oiled bowl, turning over once. Cover tightly with cling wrap or a kitchen towel and let it stand about two hours.
Make the stuffing:
Place the butternut squash cubes in a single layer on a baking sheet, spray with some oil, and bake in a preheated oven at 400 degrees for 35-40 minutes or until a knife inserted in the center of a cube goes cleanly through. Set aside.
Heat oil in a saucepan. Add the onions and minced green chili and cook until the onion is soft, stirring now and then. Add the turmeric and stir-fry for about 30 seconds.
Add the tempeh and the butternut squash. Use a potato masher to break the squash and tempeh further.
Add the garam masala and salt to taste. Add the green onions and mix well.
At this stage, preferably put the mixture in a food processor and pulse a few times until the mixture is evenly broken down. You don't want any big pieces of onion or tempeh breaking through your naan.
Make the stuffed naan:
After the dough has risen, turn it out onto a flat surface and divide into eight portions.
Shape each into a round and cover with a kitchen towel. Let it stand for 10 minutes.
Use a rolling pin or your hands to shape each round into a five-inch circle. Place about 2 tbsp of stuffing inside the ball and gather up the sides. Seal at the top.
Roll each circle out into a teardrop-shaped naan, about 7 inches in length (or any shape you please. Teardrops are more traditional).
Preheat the oven to 500 degrees.
Place as many naans as will fit in a single layer, side by side on a baking sheet.
Bake on the lowest rack of the oven about 8 minutes, turning once halfway through baking. If you wish, spray some oil after flipping and sprinkle on some sesame seeds, then continue to bake.
Serve hot with vegan raita.