In the bowl of your stand mixer or large bowl if you are kneading by hand, combine the yeast, water, and sugar. Let stand for approximately 10 minutes or until the mixture begins to foam/bubble.
Add the milk, yogurt (or sour cream), flour, baking powder, baking soda, and salt. If using a stand mixer, attach the dough hook and knead until the dough comes together. The dough should be wet and sticky, but if it's too sticky to handle, add a little bit more flour until it comes together, but is still sticky. If you are kneading by hand, lightly flour a surface and knead the dough for about 2 minutes. After the dough has been kneaded, work the dough into a ball with generously-floured hands. Place the ball into a lightly oiled. Cover with plastic wrap and let rise for about an hour, or until the dough has doubled in size.
Pour the dough out onto a very lightly floured surface, and slice the dough into 8 equal pieces. Roll each piece into a circle/oval to approximately 1/4-inch thick.
Heat a large skillet over medium-high heat. I used a cast iron skillet for this step. Spray the skillet with a nonstick spray or brush lightly with oil. While the pan is heating up, melt the butter in 20-second increments in the microwave. Alternatively, you may melt the butter on the stove top. Brush each piece of naan with the butter as you place it on the hot skillet. Once you have placed the naan in the skillet, immediately cover. After about 1-2 minutes, flip the naan. Brush the other side with butter, and cover the naan again. Cook for 2 minutes more. The naan should have large bubbles that are browned. Transfer the naan to a plate that has been lined with a tea towel. Repeat this step for the remaining naan.
Serve the naan immediately garnished with fresh parsley. Store at room temperature, wrapped in foil, for a day or two.