To toast coconut, spread it on a cookie sheet and bake at 375° for about 8-10 minutes, stirring often. Let cool.
Combine all topping ingredients in a small bowl and mix till crumbly. Set aside
For batter, whisk together flour, baking powder, baking soda, and salt. Set aside.
In a large mixing bowl, cream the butter and sugar. Beat in the eggs, sour cream, vanilla, and coconut extract. Add the dry ingredients and chocolate chips and stir gently till just moistened.
Spread batter into two 9" round cake pans that have been sprayed with non-stick spray. Divide the topping evenly between the two pans.
Bake at 350° for 28-35 minutes or until a toothpick inserted in the middle comes out clean.