Bake in the preheated oven at 160 degrees C for 40-45 minutes, or until it passes the toothpick test.
Do not open the oven during the first 15 minutes of baking. When it's done, turn off the heat and leave in the hot oven, with the door closed, for another 15 minutes.
You'll notice that, while baking, the top forms a dome shape, which usually sinks back when the cake starts to cool, then it becomes perfectly straight.