In a large mixing bowl, combine the sourdough starter, warm water, and flour.
Mix until smooth, cover with a damp cloth, and let sit at room temperature for 4–6 hours, or until bubbly and active.
2. Make the Dough:
In another large bowl, combine the flour, sugar, and salt.
Add warm milk, melted butter, beaten egg, vanilla extract, and the active sourdough starter.
Mix until a sticky dough forms.
3. Knead the Dough:
Transfer to a floured surface and knead 8–10 minutes until smooth and elastic (or use a stand mixer with a dough hook).
4. First Rise:
Place dough in a greased bowl, cover with a damp cloth, and let rise in a warm spot for 3–4 hours, until doubled in size.
5. Shape the Buns:
Punch down the dough to release air.
Divide into 12–15 equal portions and shape each into a ball.
Arrange in a greased 9×13-inch baking dish or on a baking sheet.
6. Second Rise:
Cover with a damp cloth and let rise 2–3 hours, until doubled in size.
7. Bake:
Preheat oven to 375°F (190°C).
Bake 20–25 minutes until golden brown and hollow-sounding when tapped.
8. Cool and Serve:
Let buns cool in the pan for 10 minutes, then transfer to a wire rack to cool completely.
These buns are soft, slightly tangy from the sourdough, and perfect for sandwiches or simply with butter.
