Instructions

• Preheat the oven to 350°F (180°C). Lightly grease an 8-inch (20 cm) cake pan with some of the extra unsalted butter and line the base with a round of parchment paper.
• In a medium bowl, whisk together 1 1/4 cups (150 g) all-purpose flour, 1 teaspoon baking powder, and 1/2 teaspoon salt. Set aside.
• In a small saucepan over medium heat, combine 3 tablespoons (40 g) light brown sugar, 1 tablespoon (15 ml) water, 1 teaspoon ground cinnamon, and 1/4 teaspoon ground ginger. Stir constantly until the sugar dissolves and the mixture is smooth and just begins to bubble, about 1–2 minutes. Remove from heat.
• Pour the caramel mixture into the prepared pan and spread it evenly over the base.
• Arrange the 4 medium (450 g) plums, pitted and quartered, in a single layer over the caramel, cut sides down, in a decorative pattern.
• In a large mixing bowl, use a hand mixer to beat 1/2 cup (113 g) softened unsalted butter and 3/4 cup (150 g) granulated sugar until light and fluffy, about 2–3 minutes.
• Add the 2 large eggs (at room temperature) one at a time, beating until each egg is incorporated and scraping down the sides of the bowl as needed. (Do not add vanilla — it is not in the ingredient list.)
• Add the dry ingredients to the butter mixture and mix on low speed just until combined. Do not overmix; the batter will be thick.
• Spoon the batter evenly over the plums, spreading gently to cover the fruit and smoothing the top with a spatula.
• Bake in the preheated oven for 35–40 minutes, or until a toothpick inserted into the center of the cake (avoiding the fruit) comes out clean or with a few moist crumbs.
• Remove the pan from the oven and set it on a wire rack. Let the cake cool in the pan for 10 minutes. Run a knife around the edge if needed to loosen.
• Place a serving plate over the pan and carefully invert the cake onto the plate. Peel off the parchment paper, then serve warm or at room temperature.