In the bowl of the stand mixer, stir together the flour, salt, baking powder, sugar, and yeast. In the small bowl, mix together the egg, yogurt, and milk. Pour the egg mixture into the dry ingredients and stir for about 1 minute, until the dry ingredients are completely incorporated into the wet ingredients.
Increase machine speed to 2, and knead the dough until it is smooth and shiny. Remove the bowl from the mixer and cover with a towel. Leave in a warm place to rise until the dough doubles in size, about an hour.
Put a baking stone or heavy baking sheet on the lowest rack of your oven. Preheat the oven to the hottest setting, most likely 450° to 500° F depending on your oven.
Divide the dough into eight pieces and form into teardrop shapes with your hands, about 6 to 8 inches across. I press the dough out with the palm of my hand, then I pick up the dough and turn it in circles in my hands until I get the teardrop shape.
Cook two or three pieces at a time. Drop the dough onto the hot stone and shut the oven door, watching until they are just starting to turn brown in places, about 3 to 5 minutes.
Remove the naan and lay on a board. Smear on the garlic butter as soon as they come out of the oven and sprinkle toasted sesame seeds on top. Serve warm with a nice curry.