Preheat oven to 350°F and line a 9×13-inch pan with aluminum foil, making sure it hangs over the sides a bit, then grease with non-stick spray.
Spread pecans, brown sugar and 1 cup of the coconut in the pan. Sprinkle with cinnamon and salt, and drizzle with vanilla extract and melted butter.
In a medium bowl, beat together the 2/3 cup butter and 1 cup brown sugar on medium speed with an electric mixer until creamy. Continue mixing on low, and add eggs one at a time, followed by vanilla, mixing until thoroughly combined.
Add baking powder and salt, mixing on low until incorporated. Add 1/2 of the flour, followed by milk, and then remaining flour, mixing well after each addition.
Pour batter over pecan mixture in prepared pan and bake until a toothpick inserted into the center comes out clean, about 35-40 minutes.
Run a knife around the sides of the pan to loosen and let cake cool in pan for 5 minutes. Invert cake onto a platter, using foil overhang as needed. Let cool 15 minutes before serving. Enjoy!