Warm milk mixture:

In a small bowl or glass measuring cup, whisk together 1/3 cup milk and 1/3 cup sour cream or yogurt. Heat in the microwave in 20-second bursts until lukewarm (like bath water; if too hot, chill briefly in fridge).

Activate yeast:

Stir in 1 tablespoon sugar and 1 tablespoon yeast. Let stand at room temperature for about 5 minutes until frothy and bubbly. If no foam appears, discard and begin again.

Add egg and oil:

Add 1 egg and 3 tablespoons oil to the yeast mixture. Beat the egg and combine thoroughly.

Knead dough:

In a large bowl or stand mixer bowl, mix 2 cups flour and 1 teaspoon salt. Pour in the yeast mixture and stir. Attach dough hook (or knead by hand on a floured surface). Knead for about 5 minutes, incorporating up to 1/2 cup additional flour as needed to achieve a smooth, elastic, slightly tacky dough.

First rise:

Lightly oil or spray a large bowl. Shape the dough into a ball, place it in the bowl, and turn to coat. Cover with plastic wrap or a tea towel and let rise in a warm spot for 1 hour (or 45 minutes if short on time).

Divide and rest:

Punch down the dough and divide into 6 or 8 equal portions (6 yields thicker naan). Set on a lightly floured surface, cover with a tea towel, and rest for 10 minutes.

Shape naan:

Flatten one dough ball with your palm, then roll into an oval or triangle about 9x5 inches. Let rest 3-5 minutes before cooking for a thicker texture.

Cook naan:

Preheat a 12-inch cast iron skillet or griddle over medium to medium-low heat. Generously oil or spray the surface. Cook one naan at a time: first side for 1-2 minutes until bubbles appear across the top, then flip and cook the second side for about 1 minute. Adjust heat to avoid scorching.

Make garlic butter:

In a small bowl, melt 1/4 cup salted butter. Stir in 1-2 minced garlic cloves if desired.

Brush and serve:

Remove each naan from the pan; immediately brush with garlic butter, sprinkle with parsley, and serve hot. To keep warm, place naan on a cooling rack in a 170°F (75°C) oven.

Store leftovers:

Store leftovers in an airtight container or zip-top bag for up to 3 days.