Place the fig slices in a large bowl. Add 1 tablespoon lemon juice, ¼ cup granulated sugar, and 1 tablespoon cornstarch. Toss gently to coat, being careful not to break up the tender fig slices.
Cook the sugar:
Lightly grease a 9-inch cake pan. Set aside.
Melt 3 tablespoons of butter in a small pot over medium heat. Once melted, add ½ cup brown sugar and 2 teaspoons corn syrup. Stir to combine. Cook over medium heat for 3 to 4 minutes, stirring occasionally, until the sugar dissolves and the mixture darkens slightly in color.
Pour the mixture into the prepared cake pan and smooth it into an even layer. Transfer to the refrigerator for 15 minutes.
Make the batter:
Combine 4 tablespoons of evaporated milk with 4 tablespoons of water in a small bowl. Set aside.
Sift 1 cup cake flour, 1 teaspoon baking powder, and ¼ teaspoon kosher salt into a small bowl. Set aside. Using an electric hand-mixer, cream 4 tablespoons butter with ½ cup granulated sugar in a large mixing bowl until light and fluffy. Add 1 egg and mix until creamy.
Add half the dry ingredients and beat with the mixer until just combined. Add half the evaporated milk mixture and beat until incorporated. Add the remaining dry ingredients and the remaining evaporated milk mixture, along with 1 teaspoon vanilla extract. Beat until just combined. Don’t over-mix!
Assemble the cake:
Remove the cake pan from the refrigerator. Arrange the figs, cut-side down, in single layers. Use your hands to press the figs gently into the caramel layer. Spoon any excess liquid from the bowl over the figs.
Spoon the batter over the figs and smooth it into an even layer.
Bake the upside-down cake:
Transfer the cake to the oven for 43 to 48 minutes or until a toothpick inserted into the center of the cake comes out clean.
Let the cake stand for at least 30 to 45 minutes at room temperature.
To serve:
Place a large plate over the cake pan and carefully flip the cake onto the plate. Use a small butter knife to tap over the pan to encourage the release of the cake. Once the cake has been transferred to the plate, cut and serve with whipped cream on top. Enjoy!
Notes
Note 1: This recipe uses 4 tablespoons of evaporated milk, which needs to be diluted with 4 tablespoons of water. If you don’t have evaporated milk, replace it with 8 tablespoons of whole milk and omit the water completely.