The original biscocho was actually made from bread that was about to expire. Butter or margarine was just added together with sugar on top and the bread goes back in the oven. Now it has evolved for some bakeshops actually baked bread intended to be made as biscocho and some use condensed milk to have a more chewy topping. This reminds of my favorite brand when I was a kid, the now extinct Yen's Biscocho which had those dried, almost chewy condensed milk on top.
Two of the more famous brands of biscocho in Iloilo City are Wewin's and Biscocho Haus. But there are numerous bakeshops having their own versions. Tibiao's biscocho has almost become like buttered toasts due to generous toppings. Biscocho is widely available in all groceries and bakeshops in the city and as the whole country as well.