Preheat the oven to 350°F (175°C). Grease and flour a 9-inch (23 cm) round cake pan.
In a medium bowl, whisk together the flour, baking powder, baking soda, and salt. Set aside.
In a large bowl, beat together the sugar, eggs, and vanilla extract until light and fluffy. Slowly add the oil and lemon juice and continue to beat until combined.
Stir in the flour mixture and mix until just combined.
Fold in the zested lemon and the diced plums.
Spread the batter into the prepared cake pan and sprinkle with the brown sugar. Bake for 30 minutes, or until a toothpick inserted into the center of the cake comes out clean.
Allow the cake to cool for 10 minutes before removing from the pan and transferring to a wire rack to cool completely.
To serve, dust the top of the cake with powdered sugar.
Interesting Facts
Plums are a rich source of antioxidants and vitamin C.
Lemons are a great source of vitamin C and help to boost the immune system.
This cake is perfect for any occasion, from a casual brunch to an elegant dinner party.