In a small bowl, sprinkle the yeast over ¼ cup warm (105° to 115°F) water and let stand until creamy, 5 to 10 minutes. Stir to dissolve the yeast.

In a medium saucepan, heat the buttermilk, stirring constantly, just until warm (about 100°F). Or place the buttermilk in a 1-quart glass measuring cup and microwave on High for 1 minute, stirring occasionally, until warm. Transfer the buttermilk to a bowl and stir in the dissolved yeast mixture, melted butter, eggs, sugar, baking soda, and salt.

To make the dough by hand, transfer the liquid ingredients to a large bowl. Gradually stir in enough of the flour to form a shaggy dough. Turn out onto a lightly floured work surface. Knead the dough, adding more flour as needed, until the dough is smooth and elastic, 8 to 10 minutes. Form the dough into a ball.

To make the dough in a heavy-duty standing mixer, pour the liquid ingredients in the mixer bowl, and attach the paddle blade. With the machine on low speed, gradually add enough of the flour to make a stiff dough that collects around the blade. Change to the dough hook. Knead the dough in the machine, adding more flour as needed to make an elastic dough, about 8 minutes. Transfer to a lightly floured work surface and knead by hand until smooth, about 2 minutes. Form the dough into a ball.

To make the dough in a food processor, fit an 11-cup (or larger)-capacity machine with the metal blade. Make the dough in two batches. Place 2½ cups of the flour in the machine and pulse to combine. With the machine running, pour about half of the liquid ingredients through the feed tube to form a soft ball of dough that rides on top of the blade. Process for 45 seconds to knead the dough. Transfer the dough to a lightly floured work surface and cover with plastic wrap. Repeat with the remaining ingredients. Knead the two portions of dough together by hand until smooth and combined. Form the dough into a ball.

Place the dough in a large, buttered bowl. Turn the dough to coat with the butter, and turn the dough smooth side up. Cover tightly with plastic wrap and let stand in a warm place until doubled in volume (if you poke the dough with your finger, an impression will remain), about 1¼ hours.

Lightly butter two 9-inch round cake pans. Punch down the dough and knead briefly on an unfloured work surface. Cut the dough into 18 equal pieces. (This is easiest to do by cutting the dough into thirds, then each third in half, and each half into 3 pieces.) Cover the cut pieces of dough with a piece of plastic wrap. Place a piece of dough on the work surface. Using the sides of your hands, tuck the dough underneath itself, turning the dough as you tuck, stretching the top surface and eventually forming a taut ball. Transfer the roll to a prepared pan. Repeat with the remaining piece of dough, allowing 9 balls per pan. Cover loosely with plastic wrap and let stand in a warm place until almost doubled in volume, about 40 minutes.

Preheat the oven to 375°F. Brush the tops of the rolls lightly with melted butter and sprinkle with the seeds, if using. Bake until golden brown, 20 to 25 minutes. Remove from the pans and serve warm.

VARIATIONS

Knot Rolls: Lightly butter two baking sheets. Work with one piece of dough at a time, keeping the others covered with plastic wrap. Roll the dough between your palms into a thick rope. Place the rope on an unfloured work surface. Put your hands on top of the dough and roll it back and forth, stretching the dough into a 9-inch-long rope. Tie the dough into an overhand knot, with the knot positioned in the center of the rope. Place the knots 2 inches apart on the prepared baking sheets. Cover loosely with plastic wrap and let rise until almost doubled in size. Bake as directed above.

Cloverleaf Rolls: Lightly butter 18 muffin cups. Cut each piece of dough into thirds and form each piece into a small, taut ball. Place 3 balls, smooth sides up, in each muffin tin. Cover loosely with plastic wrap and let rise until almost doubled. Bake as directed.