Step 1

Make the Basic Dinner-Roll Dough with no mix-ins. Let rise as directed. Lightly coat 2 baking sheets with cooking spray. Turn the dough out onto a lightly floured surface. Lightly flour the top of the dough and pat it into a rectangle. Cut the dough into 24 equal pieces with a bench scraper or chef's knife.

Step 2

Gently roll each piece of dough into a ball; arrange on the prepared baking sheets. Loosely cover with plastic wrap and let stand until puffy, about 45 minutes.

Step 3

Position racks in the upper and lower thirds of the oven; preheat to 375 degrees F.

Step 4

Brush the rolls with some of the melted butter and cut an X in the center of each with kitchen shears or a small knife. Sprinkle the tops with sea salt. Bake, switching and rotating the baking sheets halfway through, until the rolls are golden brown, about 25 minutes. Let cool 5 minutes, then brush with the remaining melted butter. Transfer to a rack to cool completely.

Step 5

Warm the milk and 1/2 cup water in a small saucepan or in the microwave until very warm (110 degrees F). Transfer to the bowl of a stand mixer fitted with the dough hook; mix in the sugar, yeast and 1 cup flour until combined but still lumpy. Let stand until the mixture is very bubbly, about 30 minutes.

Step 6

Add the butter, salt and 2 cups flour; mix on medium speed until smooth and elastic, 2 to 3 minutes. Mix in the eggs until combined, scraping the bottom and side of the bowl as needed. Add 1 1/4 cups flour and the mix-ins, if using; mix until the dough is smooth and starts to gather into a loose ball, about 4 minutes. The dough should be slightly sticky; if it's too wet, add the remaining 1/4 cup flour.

Step 7

Lightly oil a large bowl; scrape the dough into the bowl and turn to coat with the oil. Cover with plastic wrap and set aside in a warm place until doubled in size, about 2 hours.