Bubble Buns

Place water in bowl of stand mixer and sprinkle yeast over. Let stand until bubbly, about 10 minutes. Stir in butter, sour cream, sugar, egg and vanilla. Beat in 2 cups of flour, the salt and baking soda until incorporated. Add remaining flour and continue to mix until a smooth, soft dough forms.
Knead dough until smooth, using the dough hook attachment, about 2-3 minutes. Cover with plastic wrap. Let rise in a warm place until doubled in size, about 1 hour.
Grease a 12-cup muffin pan. Roll dough into a long cylinder and then divide into 12 equal portions. Divide each of the 12 portions into 5 equal pieces and roll each piece into a ball.
Arrange four balls in the bottom of a prepared muffin cup. Using your fingertip, make a small well in the center and press in the fifth ball. Repeat with remaining dough and muffin cups.
Cover buns loosely with plastic wrap and let rise in a warm place until puffy and have doubled in size, about 40 minutes.
Preheat oven to 350°F. Bake buns until golden, 20-22 minutes. Let cool in pan. Transfer the cooled buns to a wire rack. Place a piece of parchment paper underneath wire rack.
In a small bowl, mix powdered sugar and milk and stir until smooth. You may need slightly more milk if your glaze is too thick. Drizzle top of bun with glaze. If you pour enough it will slide off and glaze the rest of the bun on its own. After each one, place sprinkles on top. You want to add the sprinkles while the glaze is wet as it dries quickly and the sprinkles won't stick once the glaze is dry. Repeat with remaining buns.

Ingredients

Dough

Glaze

Instructions