Preheat the oven to 180°C (350°F).
Sift the flour and baking powder into a bowl and set it aside.
Place the sugar, eggs, and vanilla in an electric mixer bowl and mix the ingredients well.
Gradually pour in the oil, liquid milk, and orange juice while continuing to mix.
Add the sifted flour mixture and orange zest, and mix until you have a smooth, consistent batter.
Grease a baking pan with a little olive oil and pour the cake batter into it.
Bake the pan in the oven for about 45 minutes until the cake is cooked through and golden in color.
Slice the orange dessert and serve it with a cup of hot tea.