In a large bowl, combine the flour, yeast, sugar, and salt. Whisk to combine.
In a separate bowl, whisk together the warm milk, yogurt, and vegetable oil.
Pour the wet ingredients into the dry ingredients and mix until a shaggy dough forms. Turn the dough out onto a lightly floured surface and knead for 8-10 minutes, or until smooth and elastic.
Place the dough in a lightly oiled bowl, cover with plastic wrap, and let it rise in a warm place for 1-1.5 hours, or until doubled in size.
Punch down the dough and divide it into 8 equal portions. Roll each portion into a ball.
On a lightly floured surface, roll out each ball into an oval shape, about 8-10 inches long and 0.25 inches thick.
Heat a cast-iron skillet or a griddle over medium-high heat. Cook the naan for 2-3 minutes per side, or until puffed up and golden brown spots appear.
While the naan is still hot, brush with melted butter and sprinkle with chopped cilantro, if desired.
Notes
Naan is best served warm, immediately after cooking.