¾ cup Buttermilk or ½ cup Yogurt mixed with ¼ cup Milk
2 tsp. Salt
2 tsp. instant Yeast or 2 tbsp. fresh Yeast
6 tbsp. unsalted Butter, melted
4 cups all-purpose Flour, plus more for dusting
For the Nut-Caramel Sauce:
4 tbsp. unsalted Butter
⅔ cup Brown Sugar
3 tbsp. Buttermilk or Yogurt mixed with Milk
1 cup any Nut of your choice, toasted and coarsely chopped
Pinch of Kosher Salt
For the Filling:
⅔ cup Brown Sugar
1 tbsp. ground Cinnamon
2 tablespoons unsalted butter, melted
Make the dough: Whisk the eggs. Add the sugar, buttermilk, salt, yeast, and melted butter and whisk until homogeneous (the mixture may clump up a bit—this is OK). Add the flour and stir with a wooden spoon.
Knead the dough for a few minutes, until it’s smooth and silky. Return to the bowl, cover with plastic wrap, and allow to rise at room temperature until roughly doubled in volume, about 2 hours.
Make the nut-caramel sauce: Cook the butter and brown sugar in a small saucepan over medium-high heat, stirring occasionally, until the sugar is completely dissolved and the mixture is bubbling, about 2 minutes. Add the buttermilk, pecans, and salt and stir to combine, then pour the mixture evenly over the bottom of a 13-by-9-inch baking dish.
Make the filling: Combine the sugar and cinnamon in a small bowl and set aside.
Roll out the dough: Turn the dough out onto a floured surface and lightly flour it. Shape into a rough rectangle with your hands and then, using a rolling pin, roll into a rectangle about 16 inches long and 12 inches wide, with a short end toward you. Brush with the melted butter, leaving a 1-inch border along the top edge. Sprinkle with the cinnamon and sugar mixture and spread it with your hands until the buttered portion is evenly coated. Roll the dough up jelly-roll-style into a tight cylinder, using a bench scraper as necessary to assist you. Pinch the seam shut and turn the dough so that it's seam side down. Use your hands to even out its shape.
Use a sharp knife to cut the roll into 12 even slices: The easiest way to do this is to cut it in half, cut each half in half, and then cut each section into thirds. Nestle the 12 rolls with the swirl pattern facing up in the prepared baking dish, making sure the slices from the ends of the log go cut side down. Cover with plastic wrap and allow to rise until roughly doubled in volume, about 2 hours. The rolls should be well puffed and pressed tightly against each other.
While the dough is rising, adjust an oven rack to the middle position and preheat the oven to 350°F. Transfer the baking dish to the oven and bake until the buns are golden brown and well puffed, about 30 minutes, rotating the dish once. Allow to rest for 5 minutes, then invert the buns onto a serving platter; scrape out any excess goo from the pan and spoon over the buns.
Serve with a cold glass of milk or a vanilla ice-cream scoop.