Ingredients:

For the topping:

• 1/4 cup unsalted butter
• 1/2 cup packed brown sugar
• 4-5 ripe plums, pitted and sliced

For the cake batter:

• 1 1/2 cups plain flour
• 1 1/2 teaspoons baking powder
• 2 tsp orange zest
• 1/2 tsp ground cardamon
• 1/2 teaspoon salt
• 1/2 cup unsalted butter, softened
• 1 cup white sugar
• 2 large eggs
• 1 teaspoon vanilla extract
• 1/2 cup milk

Instructions:

1. Preheat your oven to 350°F (175°C). Grease a 9-inch round cake pan and set aside.
2. In a small saucepan, melt 1/4 cup of butter over medium heat. Stir in the brown sugar until it dissolves. Pour the mixture into the prepared cake pan, spreading it evenly.
3. Arrange the plum slices in a single layer over the butter and sugar mixture in the pan.
4. In a medium bowl, whisk together the flour, baking powder, orange zest, cardamon and salt. Set aside.
5. In a large mixing bowl, cream together 1/2 cup of butter and granulated sugar until light and fluffy.
6. Add the eggs one at a time, beating well after each addition. Stir in the vanilla extract.
7. Gradually add the dry ingredients to the wet ingredients, alternating with the milk. Begin and end with the dry ingredients. Mix until just combined.
8. Pour the batter over the plum slices in the cake pan, spreading it evenly.
9. Bake in the preheated oven for 40-45 minutes or until a toothpick inserted into the center comes out clean.
10. Allow the cake to cool in the pan for about 10 minutes. Then, place a serving plate over the top of the pan and carefully invert the cake onto the plate. Allow it to cool completely before serving.

Enjoy your delicious Plum Upside-Down Cake!