Preheat oven to 350°F. Lightly grease a 9×13 inch pan and set aside.
In a medium bowl, pour the boiling water over the oats. Set aside.
In a separate bowl, mix together the flour, salt, soda and cinnamon. Set aside.
Cream together the 1/2 cup of butter, sugar, 1 cup of brown sugar, eggs and vanilla until smooth. Slowly add in the flour mixture until fully incorporated.
Add the softened oats until just combined.
Pour batter into the prepared pan, and bake in the preheated oven for 35 to 40 minutes.
Meanwhile, in a saucepan, combine the milk, 1/2 cup of butter, 1/4 cup of brown sugar and 3/4 cup white sugar until the butter has melted and the mixture is fully combined. Add in the coconut and chopped pecans.
Remove the cake from oven. Set oven temperature to broil.
Spread the coconut mixture on the warm cake.
Place the cake under the broiler for 2 to 3 minutes. Keep an eye on it! Remove from oven, and allow to cool before cutting into slices.