Place an oven rack in the middle position and heat the oven to 350 degrees. Grease and flour a 9x13 inch baking pan or glass baking dish.
In a medium bowl, whisk together the flour, baking powder, and salt. Set aside.
Heat together the butter and milk just until the butter has completely melted. Remove from the heat and mix in the vanilla. Set aside.
Use an electric mixer to beat together the eggs and sugar in a large mixing bowl.
Alternately fold the flour and warm milk mixture into the egg mixture until completely incorporated.
Transfer the finished batter to the prepared baking dish or pan.
Bake until a toothpick inserted into the center comes out clean (about 30-35 minutes).
Make the Topping:
While the cake is cooling, make the topping by combining the butter, brown sugar, evaporated milk, and coconut.
Spread the topping evenly over the baked layer.
Turn on the oven broiler element; transfer the pan to the oven and broil until brown and bubbly.
Remove from the oven. Let cool briefly. Slice, serve, and enjoy!
Notes
Be sure to both grease and flour the pan or baking dish to ensure your dessert slides out of the pan with ease.
To make ahead, bake and top as directed in the recipe, but wait to broil it until just before you’re ready to serve.
To store, slice into individual serving-sized pieces and wrap with plastic wrap before storing in an airtight container. They'll stay fresh in the fridge for up to 4 days or in the freezer for up to 3 months.
Serve either warm or at room temperature. To reheat individual servings, simply pop them in the microwave and heat in 30-second increments until warmed through.