for the dough:
1 package active dry yeast
1/4 cup warm water
3 Tablespoons unsalted butter, melted
2/3 cup sour cream
3 Tablespoons sugar
1 large egg
1 teaspoon vanilla extract
2 1/2 cups flour
1/2 teaspoon salt
1/4 teaspoon baking soda
for the cinnamon-sugar coating:
1/3 cup packed brown sugar
1 teaspoon cinnamon
3 Tablespoons unsalted butter, melted
for the vanilla glaze:
1 3/4 cups confectioners' sugar
1 Tablespoon unsalted butter, melted
1 Tablespoon milk, preferably whole
1 teaspoon vanilla extract
Start by making the dough. In a large mixing bowl, sprinkle the yeast over the water and let it stand until bubbly, 5 to 10 minutes. Stir in the butter, sour cream, sugar, egg, and vanilla. Beat in 2 cups of the flour, the salt, and the baking soda until incorporated. Add the remaining 1/2 cup flour and continue mixing until a smooth, soft dough forms.
Turn the dough out onto a lightly floured surface and knead it until smooth, about 3 minutes. As you work, add more flour if the dough is sticky (do not exceed 2 Tablespoons). Place the dough back in the mixing bowl and cover the bowl with plastic wrap. Let the dough rise in a warm place until it has doubled in size, about 1 hour.
Lightly coat a 12-cup muffin pan with nonstick spray or butter, then flour the cups and tap out the excess.
In a small bowl, blend the sugar and cinnamon for the coating. Place the melted butter in a small, shallow dish.
Gently punch down the dough to deflate it. Form it into a long cylinder and divide it into 12 equal portions.
Using kitchen scissors or a dough scraper, divide each portion into 6 equal pieces, then roll each piece into a ball.
To make a bun, coat six balls with melted butter, then roll them in the cinnamon-sugar mixture. Arrange five of the balls in the bottom of a prepared muffin cup. With your fingertip, make a small well and press the sixth ball in the center. Repeat with the remaining dough. Loosely cover the buns wiht plastic wrap and let them rise in a warm place until they're puffy and have doubled in size, about 40 minutes. Heat the oven to 350.
Bake the buns on the center rack until golden, 20-22 minutes. Transfer the pan to a wire rack placed over a sheet of waxed paper or aluminum foil to cool for 5-8 minutes, then tilt the pan and gently tap it on a work surface to release the buns. If needed, a knife can be used to release them from the pan. Place the buns on the wire rack.



