In the bowl of an electric stand mixer, combine the instant yeast with the lukewarm water. Let stand for 5 minutes.
3 tsp instant yeast | 3/4 cup plus 3 tablespoons lukewarm water
Add the dry milk powder, bread flour, 1 cup of all-purpose flour, granulated sugar, baking powder, salt, and egg. Attach the dough hook and mix until the dough comes together and climbs up the dough hook. Knead with the machine for about 3 minutes.
1/4 cup dry milk powder | 3 cups bread flour | 1 cup all-purpose flour | 1/2 cup granulated sugar | 1 1/2 tsp baking powder | 1 tsp fine salt | 1 large egg
Add the butter, 1 to 2 tablespoons at a time.
7 tbsp unsalted butter
It will take several minutes to incorporate the butter, and you might have to lift the dough off the dough hook with a spatula from time to time. When the butter has incorporated fully into the dough (it will be sticky and batter-like), continue kneading, adding small amounts of all-purpose flour until the dough comes away from the sides of the bowl. Knead for about 5 to 6 minutes longer, until smooth and elastic.
Line a 9-by-13-by-2-inch baking pan with parchment paper, leaving overhang on the long sides. Press the dough evenly into the pan. Cover with plastic wrap, let rest at room temperature for 45 minutes, then refrigerate overnight.
The next morning, lift the dough out of the pan using the parchment overhang and set it on a lightly floured surface (or a large baking sheet). Remove the parchment. Butter the same 9-by-13-inch pan and set aside.
Butter, for the baking pan
Combine 1 cup of brown sugar and 1/2 cup (1 stick) of butter in a saucepan. Bring to a boil and continue boiling for 1 minute. Remove from the heat and stir in the 1 cup of pecan halves. Pour into the buttered baking pan and spread to cover the bottom.
½ cup butter | 1 cup pecan halves | 1 cups packed light brown sugar
In a small bowl, combine the remaining 1/2 cup of brown sugar with the cinnamon and the finely chopped pecans, if using.
1 tbsp ground cinnamon | 1/2 cup finely chopped pecans (optional) | ½ cups packed light brown sugar
Roll the dough out into a rectangle about 15 inches long and 9 inches wide. Spread the remaining 1/2 cup of butter over the dough to within about 1/2 inch along the long ends.
½ cup butter
Sprinkle with the brown sugar and cinnamon mixture. Starting at a long end, roll the dough up, jelly-roll style. Cut the roll into 12 rounds. Place the slices atop the butter-pecan mixture in the baking pan. Cover the dough with a kitchen towel and let rest for 30 minutes.
Heat the oven to 350 F.
Bake the buns for about 45 minutes, or until golden brown. Let stand for 5 minutes, and then carefully invert them onto a large platter or a large shallow baking pan, such as a jelly roll pan.
Spoon any syrup left in the pan over the buns. Pull apart and serve warm.