Preheat oven to 350º. Line a 9 x 5 inch loaf pan with parchment paper and spray with cooking spray.
In a large bowl, whisk together the flour, sugar, baking powder, baking soda, and salt. In a separate bowl, whisk together the eggs, buttermilk, 8 tablespoons melted butter and vanilla.
Add the wet ingredients to the dry ingredients, stirring just until combined and you can no longer see pockets of flour.
In a small bowl combine 4 tablespoons of melted butter with brown sugar, cinnamon salt and pecans.
Pour half of the batter into the loaf pan. Spoon ½ of the cinnamon mixture on top and swirl it into the batter with a knife. Add the remaining batter and top with the rest of the cinnamon mixture, swirling it into the batter.
Bake for 40 minutes, then tent with foil to prevent over browning and cook an additional 13-15 minutes. A toothpick should come out with just a few crumbs.
Let it cool in the pan on a cooling rack for an hour before removing.
Add cream cheese, butter, powdered sugar, cinnamon and 2 tablespoons of cream or milk to a mixing bowl. Beat with a hand mixer until smooth. Add additional cream depending on how thick or thin you want the frosting. Drizzle over the cake.