Whisk together oil, sugar, and eggs. Stir in egg liqueur. Fold in flour and baking powder.
Lightly grease bundt pan with oil. Transfer batter to pan and bake at 160°C/320°F with convection fan for approx. 50 min.
Turn cake out of pan and let cook completely on a wire rack. Transfer to a serving plate and dust with confectioner's sugar, if desired. Enjoy!