In a small bowl, combine the warm water, sugar, and active dry yeast. Stir gently and let it sit for 5 to 10 minutes until the mixture becomes frothy.
In a large mixing bowl, whisk together the all-purpose flour and salt.
Add the yeast mixture and vegetable oil to the flour mixture. Stir with a spoon or your hand until a rough dough forms.
Turn the dough onto a floured surface and knead for about 8 to 10 minutes until the dough is smooth and elastic. Add small amounts of flour as needed to prevent sticking.
Place the dough in a lightly oiled bowl, cover it with a clean kitchen towel or plastic wrap, and let it rise in a warm place for about 1 hour or until it doubles in size.
Once the dough has risen, punch it down gently and divide it into 6 equal portions. Roll each portion into a ball.
On a floured surface, roll each dough ball into an oval or teardrop shape about 1/4 inch thick.
Heat a large non-stick skillet or cast-iron pan over medium-high heat until hot.
Place one rolled-out dough piece onto the hot skillet. Cook for 1 to 2 minutes until bubbles form on the surface and the bottom is golden brown.
Flip the naan and cook the other side for another 1 to 2 minutes until golden brown spots appear.
Remove the naan from the skillet and immediately brush with melted butter.
Repeat the cooking and buttering process with the remaining dough pieces.
Serve warm with your favorite curries, dips, or enjoy as a flatbread.