Simmer, stirring frequently, until the mixture thickens and deepens to a golden color. This takes about 5 minutes after mixture has come to a boil).
Remove from heat and stir in 1 cup pecans and 1 cup sweetened flaked coconut. Set aside until the cake finishes cooking.
1 cup sweetened flaked coconut, 1 cup pecans
When cake comes out of the oven, poke all over with the handle of a wooden spoon. Gently spread topping evenly over the top.
Allow the cake to cool slightly before cutting into pieces and serving.
Notes
A 12-ounce can of evaporated milk divides neatly between the cake and the topping—just eyeball half for each part of the recipe.
Every oven heats differently and may need periodic recalibration. Start checking your cake a few minutes before the suggested bake time to prevent overbaking.
Keep an eye on the topping—it thickens quickly and only needs about five minutes once it begins to boil.