Make the dough. In a small saucepan over low heat (or carefully in the microwave), warm the milk and butter until the butter has melted and the temperature is hot but not scalding (you’re looking for 105°F on a thermometer). Pour the mixture into the bowl of a stand mixer fitted with the dough hook, and sprinkle the yeast and sugar overtop. Do not stir. Let sit until it foams, about eight to ten minutes. Stir in the salt.
Add 2-1/4 cups flour and mix until just combined. Add the eggs and mix until incorporated. Knead the dough on medium-high speed until a smooth batter forms, about two to three minutes. Add the remaining 2-1/2 cups flour and knead on medium until the dough comes together and forms a smooth, elastic ball, about six to eight minutes. Add a bit more flour if needed.
Add a drizzle of oil to a large bowl and turn the ball of dough around in it so it’s got a light sheen all over. Cover the bowl with plastic wrap and let the dough rise until it doubles in size, about one hour.
While the dough is rising, make the topping. Grease a 22 x 33 centimeter baking pan with a bit of butter. Melt 3/4 cup butter in a small saucepan over medium heat. Stir in the brown sugar and cinnamon, whisking until smooth. Pour into the greased baking pan. Sprinkle the bottom of the pan with chopped pecans and a pinch of salt. Set aside.
To make the filling, combine the brown sugar, chopped pecans and cinnamon in a bowl. Set aside.
When the dough is ready, punch it down and roll it out on a floured surface into a 30 x 45 centimeter rectangle. Spread the softened butter over the dough with an offset spatula, leaving a two centimeter border along the sides. Sprinkle evenly with the brown sugar, cinnamon and pecan filling mixture.
Starting at one long end, roll the dough into a log and pinch to seal the seam. With the seam side down, slice the log into 12 fat rounds; each one should be just over three fingers thick. Place in the prepared pan, cut side up and slightly spaced apart. Loosely cover with plastic wrap and let rise until puffy, about 20–25 minutes.
During this second rise, place a rack in the center of the oven and preheat to 375°F.
Once the buns have risen, remove the plastic wrap and bake the buns until golden brown, about 18–22 minutes. Let cool in the pan for three minutes, then invert onto a serving platter. Scrape any remaining filling from the pan onto the buns. Serve at once. If you don’t eat them all in one sitting, they also freeze well.