3/4 cup whole milk (105-110 degrees F)
1 1/2 teaspoons active dry yeast
2 tablespoons sugar, divided
1/3 cup unsalted butter, at room temperature
2 tablespoons chopped fresh rosemary, divided
1/2 teaspoon kosher salt
1 large egg, at room temperature
2 3/4 cups all-purpose flour, divided
1 tablespoon unsalted butter, melted
Combine milk, yeast and 1 tablespoon sugar in a small bowl; let stand until foamy, about 5 minutes.
In the bowl of an electric mixer fitted with paddle attachment, beat butter, 1 tablespoon rosemary, salt and remaining 1 tablespoon sugar on medium speed until light and fluffy, about 2 minutes. Beat in egg until well combined. Beat in yeast mixture and 1 1/2 cups flour until a smooth batter forms.
Using the dough hook, gradually add remaining 1 1/4 cups flour, 1/2 cup at a time, until a soft, smooth ball of dough is formed. The dough should feel elastic and slightly tacky to the touch. Increase speed to medium-high and beat for 3 minutes.
Lightly oil a large bowl or coat with nonstick spray; place dough in bowl, turning to coat. Cover with a clean dishtowel and let stand in a warm spot until dough has doubled in size, about 30 to 45 minutes.
Gently deflate dough by punching down. Roll into a 10-inch rope; cut into 10 1-inch pieces, pressing each piece into a disk, then shaping into a ball.
Lightly oil a 10-inch cast iron skillet or coat with nonstick spray. Place dough balls into the prepared skillet; brush tops with melted butter and sprinkle with remaining 1 tablespoon rosemary. Cover with a clean dishtowel and let stand in a warm spot until dough has doubled in size, about 30-45 minutes.
Preheat oven to 375 degrees F. Place into oven and bake until golden brown, about 20-24 minutes.