• 1 packet dry active yeast

• 1 tsp. sugar

• 1/4 cup warm water

• 4 egg yolks

• 1 egg

• 3 Tbsp. sugar

• 6 Tbsp. unsalted butter, melted

• 3/4 cup buttermilk

• 3 3/4 cups flour

• 1/2 tsp. salt

• 1 1/2 Tbsp. unsalted butter, melted

• 3/4 cup packed light brown sugar

• 1 Tbsp. ground cinnamon

• 1 cup raisins

• 2 cups powdered sugar

• 1/4 cup milk

• 1 tsp. vanilla extract

1. In the bowl of your stand mixer, add sugar and warm water. Stir to dissolve sugar in water. Sprinkle the yeast over the water and allow to sit for 10 minutes (the mixture will get bubbly)
2. Meanwhile, in a medium bowl, whisk together egg yolks, egg, melted butter, sugar and buttermilk. Pour this mixture over the yeast. Add 2 cups of flour and the salt. Stir until evenly moistened.
3. Add remaining 1 3/4 cups of flour and use the dough hook attachment on your stand mixer to knead the dough until well mixed. The dough should be soft and moist and not overly sticky. 
4. Turn dough out on a floured counter and knead for another minute. Oil a mixing bowl and place dough inside it. Cover with a towel and let sit on the counter at room temperature until it doubles in size, between 2 and 2 1/2 hours.

1. Melt butter in a small bowl, set aside.
2. Whisk together brown sugar and cinnamon, set aside.

1. Oil a 9x13-inch baking dish.
2. Turn out dough on a floured counter and roll it into a rectangle that is roughly 12-inches tall and 18-inches long. 
3. Brush the dough with melted butter. Evenly sprinkle with sugar mixture. Evenly sprinkle with raisins.
4. Roll the dough into a tight 18-inch long log. Using a sharp knife, gently saw the log into 12 buns (they'll be about 1 1/2-inches long each). (I cut my log in half, then half again, then each section into thirds to make sure each buns was roughly the same size and I didn't need to measure) 
5. Evenly arrange and spread the buns in the oiled baking dish. Cover with plastic wrap and refrigerate over night (or up to 16 hours). 
6. The next morning, allow your buns to sit at room temperature for 30 minutes before baking.
7. Heat your oven to 350ºF. Bake buns for about 30 minutes, or until their puffed and golden brown. 
8. Transfer baking dish to a cooling rack and cool slightly while you make the icing. Whisk together milk, powdered sugar and vanilla. Spread a little on each bun or drizzle it all over the baking dish.