In a 2-cup measuring cup, combine the water and sugar, stirring until the sugar is completely dissolved.
Add the yeast, stir, and set aside for 5-10 minutes.
In the bowl of a stand mixer fitted with the dough hook, combine the flour, baking powder, baking soda, and salt.
In a medium mixing bowl or 4-cup measuring cup, combine the milk and yogurt. Once the yeast mixture is frothy, stir it into the milk/yogurt, then add to the dry ingredients.
Turn the mixer on to speed 2, mix and then knead the dough for 5 or so minutes, until you get a smooth yet somewhat sticky dough. (You can add flour 1 Tablespoon at a time if, after kneading for a few minutes, it’s too sticky that it won’t clear the sides of the bowl, but the dough should still be stuck to the bottom of it; if it’s too dry to come together, you can add more warm water 1 Tablespoon at a time–try not to do these unless absolutely necessary, as they can throw off the balance and mess up the dough.)
Lightly oil a large mixing bowl, transfer the dough ball to it, cover with plastic wrap, and set somewhere warm for 1½ hours (I usually set my oven to the lowest temperature then shut it off once it reaches that, so it’ll hold some warmth for proofing without being too warm).
Once the hour and a half has passed, flour your work surface well and transfer the dough to it. Cut into 10 equal portions then let sit for 30 minutes so the dough can rest and relax the gluten a little.
Melt the butter and get out a pastry brush.Heat a dry cast iron skillet over medium heat.
Roll out the portioned out dough to ovals/circles roughly the size of your skillet.
Brush the tops with melted butter.
Place 1 in the preheated skillet, butter side down, then brush butter on the top.
Cook for 1-2 minutes, or until the edges are dry and the surface is bubbly.
Flip and cook the other side for 1-2 minutes. When done, the bubbles will be browned but the rest of the naan will still be pale.
Remove to a plate or wire rack to cool.
Repeat with the rest of the naan.
Naan can be stored in a large zip-top bag for up to 3 days or wrapped and frozen for up to 3 months.