Bloom the yeast by combining it with the warm water and sugar in a small bowl. Cover tightly with plastic wrap and set aside for about 10 minutes, allowing the mixture to become foamy and active.
In another small bowl, whisk together the milk and egg until well blended.
Meanwhile, sift the flour and salt into a large mixing bowl to aerate and evenly distribute the dry ingredients.
Create a well in the center of the sifted flour and pour in the yeast mixture, followed by the melted butter and the milk-egg mixture. Stir with a spatula until the dough starts to come together, then switch to using your hands. Bring the dough into a soft, cohesive ball without kneading excessively.
Cover the bowl with plastic wrap and set it in a warm environment for its first rise, allowing it to double in size over 1 to 1.5 hours (Note 7).
Transfer the dough onto a lightly floured surface. Divide it into six equal portions and shape each into a ball by gently stretching the outer surface and tucking the edges underneath to create a smooth, tight sphere.
Arrange the dough balls on a floured tray or plate. Dust lightly with flour, drape a lightweight tea towel over them, and let them proof again for 15 minutes. They should puff up, expanding by about 50%.
Working one at a time, flatten each dough ball gently with your palm on a floured surface. Roll out into circles about 16cm (6.5 inches) wide, aiming for a thickness between 3–4mm (roughly 0.12–0.16 inches).
Heat a cast iron skillet over high heat, lightly greased with 1/2 teaspoon of oil applied with a paper towel to prevent sticking (see Note 8 for alternative pans). Heat until you notice faint wisps of smoke.
Lay a piece of dough onto the hot skillet. Cook for 1 to 1 1/2 minutes, or until the underside is richly golden and slightly charred, with characteristic bubbles forming on the surface. Flip and cook the second side for about 1 minute until golden brown spots develop.
Continue with the remaining dough, adjusting the skillet’s heat as necessary to avoid burning.
Immediately brush the hot naan with melted ghee or butter—or garlic butter if using (Note 5). Sprinkle generously with nigella seeds and scatter with chopped cilantro. Serve while hot and fresh for best flavor and texture.