Pour warm milk (110 to 115 degrees F) into the bowl of stand mixer. Stir in yeast and the 1 teaspoon of granulated sugar, and combine. Let it stand for 10 minutes until frothy.
Set up the dough hook attachment in the stand mixer. With the mixer on low speed, mix the 2/3 cup granulated sugar and softened butter until combined. Add eggs, salt, vanilla extract and mix. Note: you can do this with a handheld mixer.
With the mixer on medium speed, add 3 cups flour, 1 cup at a time. Add the remaining flour in 1/4 cup increments as needed or until the dough pulls away from the bowl. I ended up using about 4 cups. Increase speed to medium high and mix/knead about 5 minutes. Note: you can also knead by hand.
Transfer dough to a floured surface and knead by hand a few more times, about 2 minutes. The dough should be moist, slightly sticky, and should spring back slowly when poked. Do not over-knead. Form dough into a ball and place on a lightly oiled bowl, making sure to coat the dough with oil as well. Cover tightly with plastic wrap and let it rise in a warm and draft-free environment for 1 hour or until doubled in size.
Once the dough has risen, grease a 9x13 inch baking pan with butter and spread the chopped pecans in a uniform layer. Set aside. Make the caramel: in a saucepan, add the butter, dark brown sugar, salt, and heavy cream. Bring to a boil then reduce to a simmer for 3 minutes until thickened, stirring. Pour caramel over the pecans in a uniform layer. Set aside.
Make the filling: In a medium bowl, combine the 1 cup brown sugar and 2 teaspoons cinnamon. Set aside.
Punch the risen dough and roll out to a 12x18 rectangle on a clean surface. Brush the top with melted butter and sprinkle the brown sugar and cinnamon mixture evenly. Roll the dough tightly starting from the longest side so that you have an 18-in roll, and pinch to seal the seams. Cut into 12 pieces, same size. Arranged them on top of pecans and caramel.
Cover and let rise for 30-45 minutes in a warm environment.
Meanwhile preheat oven to 375 degrees F. Once they have risen, bake for 25-30 minutes until golden brown. Let cool for a few minutes, and invert onto a large rectangular plate. Enjoy warm!