Preheat oven to 350 degrees F. Coat the bottom and sides of a 9" cake pan with melted butter. Arrange peaches and plums on bottom of pan, spacing evenly. In a small bowl, combine brown sugar and cinnamon. Sprinkle mixture over fruit and set aside.
In a medium bowl, whisk together flour and baking powder. In a separate medium bowl, using a hand mixer or stand mixer, beat together butter and granulated sugar on medium speed until light and fluffy, about 3 to 5 minutes.
To bowl with butter, beat in eggs one at a time, scraping down sides of bowl in between. Add sour cream and vanilla and beat until smooth. Slowly add the dry mixture and beat until batter is thick and creamy.
Spoon the batter into the pan and spread gently and evenly over the fruit. Place the pan on a baking sheet and bake 40 to 50 minutes, until a toothpick inserted in center comes out clean. Let cool in the pan 45 to 50 minutes, until pan feels only warm.
Run a butter knife around the edge of the cake in pan. Invert pan onto a serving dish. If desired, dust cake with confectioners' sugar to serve.
Hannaford fresh Magazine, July August 2023