In a large mixing bowl or bowl of your stand mixer, combine the water, sugar, and yeast. Allow it to proof for 10 minutes or until bubbled and foamy. Add beaten egg, Greek yogurt, kosher salt, garlic (if using), and combine. Add bread flour, 1 cup at a time, until the dough pulls away from the side of the bowl and barely sticks to your finger when you touch it. Cover bowl and allow to rise in a warm spot for 1 hour.

Using a sharp knife or just your hands, cut/tear off handfuls of dough and shape them into golfball-sized balls. Place on a greased cookie sheet or a piece of parchment. Repeat until all the dough is used. Cover and rise again for 30 minutes.

When ready to cook, roll the dough balls into ovals about 1/4" thick. Heat a cast iron skillet with a lid to medium heat (use medium-high if your stovetop seems to cook a little low--mine cooks HOT, so medium was plenty). Fill a small bowl with water and set it next to the stove. Have the melted butter and a basting brush ready.

Dip both hands in the water and pick up a piece of dough, so the dough is slightly wet on both sides. You may be able to fit a few pieces into the pan at a time. Cover with lid and cook for about 30 seconds or until the dough starts to bubble. Flip the dough, brush the cooked side with butter and, if desired, a little kosher salt. There will be some dark marks on the bread, but it shouldn't be scorched. When done, transfer the naan to a serving dish and repeat with remaining dough.