In a large bowl, mix the flour, sugar, and salt.
In a separate bowl, whisk together your fed sourdough starter, Greek yogurt, olive oil, and warm water. Pour the wet mixture into the dry ingredients and stir until it forms a shaggy dough.
Turn the dough onto a lightly floured surface. Knead for 5–6 minutes until smooth and elastic. The dough should feel soft but manageable.
Place the dough back in the bowl and cover with a clean towel. Let it rest at room temperature for 1–2 hours until slightly puffy.
Punch down the dough and divide it into 6 equal portions. Roll each piece into a ball, then flatten into a teardrop or oval shape about 1/4 inch thick.
Heat a cast-iron skillet or nonstick pan over medium-high heat. Cook each naan for 1–2 minutes per side, until bubbles form and golden brown spots appear.
Brush each warm naan with melted butter and sprinkle with chopped fresh cilantro. Serve immediately.
