Begin by mixing together the wet ingredients (including sourdough starter) in a large bowl.
Add in the dry ingredients and mix well until it forms a shaggy dough. Spritz or brush with oil, cover with plastic wrap, and then a clean tea towel and set aside to rise for 2-3 hours in a warm place, or until doubled in size.
Punch the dough down and sprinkle a little flour on your work surface. Turn the dough out onto your floured work surface and knead it for a few minutes until smooth, adding additional flour if needed.
Divide the dough into half, then half again, then half again so you have 8 pieces. Using your fingers, stretch each piece of dough out into an oval shape about 1/4-1/2" thick.
Heat your frying pan over medium-high heat. Brush the pan with melted butter or oil and then place the naan bread in the pan and allow to fry to for a minute or two, until crispy and golden, then flip and allow to cook on the other side.
Repeat with remaining dough.