In a large glass, dissolve the dry yeast and 1 teaspoon sugar with 3/4 cup warm water (about 100 degrees F). Let it sit on your counter until it's frothy, about 10 minutes.
Meanwhile, sift the flour, salt, remaining 1 teaspoon of sugar and baking powder into a large, deep bowl.
When you're ready to roll, make sure you have two bowls on your counter: one with extra flour in it, and one with water. The dough will be extremely soft and sticky-this is good! Separate the dough into 6 equal portions and lightly roll each one in the bowl of extra flour to keep them from sticking to each other.
Warm a large cast-iron skillet over high heat until it's nearly smoking. Make sure you have a lid large enough to fit the skillet and have a bowl of melted butter at the ready.
Dampen your hands in the bowl of water and pick up one of your naans, flip-flopping it from one hand to the other to lightly dampen it. Gently lay it in the skillet and set your timer for 1 minute. The dough should start to bubble.
After about 1 minute, flip the naan. It should be blistered and somewhat blackened, don't worry - that's typical of traditional naan! Cover the skillet with the lid and cook 30 seconds to 1 minute more.