In a small bowl, dissolve 2 ¼ teaspoons of active dry yeast in ¼ cup of warm water (about 110°F). Allow it to sit for 5-10 minutes, or until frothy and bubbly.

In a stand mixer bowl, combine 1 large egg, ¼ cup of granulated sugar, ¼ cup of softened unsalted butter, and ½ teaspoon of salt. Mix, then add the frothy yeast mixture and ½ cup of buttermilk, followed by 2 cups of all-purpose flour. Mix until smooth, ensuring all ingredients are incorporated.

Switch to a dough hook attachment and gradually add 1-1.5 cups of remaining flour to the mixer. Knead for about 5-7 minutes on medium speed until the dough becomes smooth and elastic. Transfer to a greased bowl, cover, and let rise in a warm place for approximately 1 hour, or until doubled in size.

Prepare the filling by mixing ⅓ cup of granulated sugar with 2 teaspoons of ground cinnamon in a small bowl. Melt 2 tablespoons of unsalted butter to use for spreading on the dough.

In a saucepan over low heat, melt ¼ cup of unsalted butter, ⅓ cup of dark brown sugar, ¼ cup of light corn syrup, and 1 teaspoon of cinnamon, stirring until smooth. Pour this mixture into a greased 13" x 9" baking pan, then sprinkle ½ cup of chopped pecans evenly over the glaze.

Roll out the dough into a rectangle about 12x18 inches. Brush with the melted butter, then sprinkle the cinnamon-sugar mixture over the top. Roll tightly and cut into 12 equal rolls, placing them in the prepared pan. Cover and let rise for another hour.

Preheat your oven to 375°F (190°C). Bake for 20-25 minutes or until golden brown and puffed.

After baking, remove from the oven and let cool for about 10 minutes. Invert the pan onto a serving plate to let the toppings flow over the buns. Serve warm.