Cake:
2 c. all-purpose flour
2 tsp. baking powder
½ tsp. salt
4 Tbsp. butter
1 c. milk
1 tsp. vanilla extract
4 eggs, room temperature
2 c. sugar
Topping:
9 Tbsp. butter, melted
¾ c. packed light brown sugar
6 Tbsp. evaporated milk
½ tsp. salt
1½ c. shredded coconut
Adjust an oven rack to the middle position and heat oven to 350°. Grease 2 (9") round cake pans. Whisk flour, baking powder and salt in a large bowl.
Heat butter and milk in a medium saucepan over medium heat until the butter melts. Stir in the vanilla. With an electric mixer on medium-high speed, beat the eggs and sugar until pale and thick, about 6 minutes. Using a rubber spatula, fold in the flour mixture and milk mixture alternately until just incorporated.
Pour batter into prepared pans. Bake until a toothpick inserted in the center comes out clean, 30-35 minutes. Let cool slightly in the pan, about 10 minutes.
For the topping, heat oven broiler. Combine the butter, brown sugar, evaporated milk, salt and coconut in a medium bowl. Spread the topping evenly over each cake. Broil until topping bubbles and just begins to brown, 3-4 minutes. Serve warm.