Preheat oven to 350 degrees F. Heat milk and butter together until milk is hot but not boiling, and butter is melted.
In mixer bowl, beat eggs and sugar together until very light. Stir in vanilla.
Mix flour, salt and baking powder together. Remove beaters and add flour mixture to egg mixture alternately with milk-butter mixture. Fold until smooth.
Spread batter in a greased 9 inch square pan. Bake for 20 minutes, until top of cake springs back when touched lightly.
Topping:
Melt butter. Add sugar, milk and coconut.
While cake is hot, carefully spread topping over. Place under hot broiler and watch until bubbly and golden.