In a large bowl, stir together the yeast and warm water. Mix in the evaporated milk, sugar, melted butter, salt, egg and half of the flour. Gradually mix in the remaining flour and cinnamon.
Turn the dough onto a lightly floured work surface and knead until the dough is smooth and pulls together, 6 to 8 minutes. Put into a lightly greased bowl, turning once to coat both sides.
In an electric mixing bowl, beat the sugar and butter together until light and fluffy. Stir in the flour until it resembles a thick paste but not crumbly. Divide into two bowls.
Place dough balls onto two parchment paper-lined (or greased) baking sheets, 3 inches apart. Pat flat and place circles of topping on top of each, patting down lightly.