Bolo de rolo is a Brazilian dessert that involves rolling a long, thin layer of cake that has been coated in guava jam into a log-like shape, creating a spiral pattern on the inside. One of the distinctive elements of a bolo de rolo is the thinness of the cake, which is usually made in sheet pans with cookie-like dough that includes flour, butter and eggs. The filling that is spread over the cake is traditionally a guava jam or marmalade, but it can really be anything from a dulce de leche to chocolate or hazelnut spreads. The dessert can be sliced and served on a plate with more of the filling on top or whipped cream. Individual slices also can be wrapped and stored for use later.
The cake batter for a bolo de rolo is made of eggs, butter, cake flour and sugar. The butter and sugar are creamed by whipping them together until smooth and light. The eggs and flour are added to complete the dough. For a lighter cake, the eggs are sometimes separated and the whites are folded into the batter before the flour is added.
The batter is then placed into a sheet pan. Depending on the setup of the kitchen, a single sheet of cake can be baked at a time, or multiple sheets can be baked simultaneously. One of the keys to creating a bolo de rolo is to spread the batter onto the sheet pans in very thin layers, because the cake will not roll if the layers are too thick. It also is important that the layers not be too thin, like a crepe, because they might dissolve into the jam, making the interior of the cake a shapeless mush.
Once spread in the sheet pans, the dough is baked for a few minutes in an oven. For the rolling process to work, the cake must cook only long enough to set and must remain moist. If the cake begins to brown or even turn a golden color, then too much moisture will have left it and the cake will break into pieces when rolled.
When the cake has cooked, it is removed from the pan and placed on a very slightly moist towel and sprinkled with powdered sugar. The guava jam or other filling is spread in a thin layer over the cake. Starting from one end, it is slowly rolled to form a cylinder. Once one sheet cake has been rolled, the process can be repeated with the next one by placing the log at the edge of the new cake and continuing the rolling. In this way, several smaller and easier to handle cakes can be combined to form a single bolo de rolo with many layers on the inside.
The finished bolo de rolo is wrapped in plastic and refrigerated to set. When done, it can be sliced for a dramatic presentation and served on a plate. The cake can be served with freshly whipped cream, drizzled with hot syrup or plated with a side of the filling used in the roll.