Throw the flour, salt and butter into a large bowl. In a pyrex cup, dissolve the sugar in 1/2 cup water. Warm the cup in the micro-wave to 110 degrees F. Stir the yeast into the sugar/water. Allow the yeast to proof for 10 minutes. Dump the yeast mixture into the flour bowl. Combine the ingredients and knead the mass for 5 minutes. Shape the dough into a large ball. Place the dough-ball in a bowl and cover with plastic wrap. Rest the dough for 2 hours at room temperature. Form the dough into 5, medium-sized balls (2 1/2 oz per ball). Place the balls on a plate. Cover the plate with plastic wrap. Allow the dough to rest for 30 minutes.
Preheat a heavy skillet, a comal or a griddle over a medium flame. With a rolling-pin, roll one dough-ball into about a 7 inch round. Place the naan on the skillet. When the bottom is golden-brown, flip it. When the second side is golden-brown, flip it for a few seconds then remove the naan. Repeat this procedure with the remaining 4 dough-balls.
Smear butter on each naan after frying. If not consuming immediately, stack the naans on a plate and cover with plastic wrap. They can be re-warmed - tortilla-style. Traditionally, naan is served hot/warm - with Curry, Tawa, Karahi, Tandori, etc.
The taste and texture of these flat-breads put the flour tortilla to shame. Naan may be used to make excellent burritos, quesadillas, sandwiches, mini-pizzas, burgers, etc.