Measure out all ingredients except the baking powder, place in a mixing bowl and stir well for 5 minutes. Add the baking powder during the last minute.
Brush a 20 x 20 x 5 cm baking pan well with oil, including the edges, and add the dough.
Place the pan in the oven and bake the cake at 160 ° C for approx. 50 - 55 minutes.
Let cool and sprinkle with powdered sugar. Before cutting and removing, carefully remove the edges from the baking pan with a knife.
The cake makes 9 very large pieces if you are really hungry or 18 small pieces, which is recommended because the nut content is very high.