Whisk together 1 cup flour, undissolved yeast, sugar and salt in a large mixer bowl. Combine water, yogurt, milk and butter in a separate bowl and stir until smooth. Gradually pour liquid mixture into flour mixture and stir until well blended. Add enough remaining flour to form a soft dough. Cover and allow to rise until doubled in size, about 15 to 20 minutes.
Divide dough into 9 equal pieces and roll into balls using oiled hands. Cover and allow to rise for 15 to 20 minutes.
Dip fingers in oil and shape each dough ball by first flattening and then gently stretching by pulling edges and lifting until about 1/8 to 1/4-inch thick. Naan flatbread is typically an elongated teardrop or rounded triangular shape.
Preheat stove top griddle or heavy bottomed skillet over medium-high heat.
Lightly oil griddle or pan. Cook in batches depending on pan size. Place flattened dough pieces onto heated cooking surface and cook for 1 to 2 minutes per side. The flatbreads are ready to turn when large bubbles appear on the top surface; bottom surface should be lightly browned.
Transfer to a plate and serve immediately or cool to room temperature and store in an airtight container for up to 1 week.