1 Granny Smith apple, peeled, cored, and diced
1/2 cup light brown sugar, lightly packed
1 tablespoon grated orange zest (2 oranges)
1/4 cup freshly squeezed orange juice
1 1/8 teaspoons ground cinnamon, divided
2 extra-large eggs, at room temperature
1 cup plus 1 tablespoon granulated sugar
1/4 pound (1 stick) unsalted butter, melted and slightly cooled
1 teaspoon pure vanilla extract
1/4 cup sour cream
1 cup all-purpose flour
1/4 teaspoon kosher salt
Preheat the oven to 325 degrees F.
Combine the cranberries, apple, brown sugar, orange zest, orange juice, and 1 teaspoon of the cinnamon in a medium bowl. Set aside.
In the bowl of an electric mixer fitted with the paddle attachment, beat the eggs on medium-high speed for 2 minutes. With the mixer on medium, add 1 cup of the granulated sugar, the butter, vanilla, and sour cream and beat just until combined. On low speed, slowly add the flour and salt.
Pour the fruit mixture evenly into a 10-inch glass pie plate. Pour the batter over the fruit, covering it completely. Combine the remaining 1 tablespoon of granulated sugar and 1/8 teaspoon of cinnamon and sprinkle it over the batter. Bake for 55 to 60 minutes, until a toothpick inserted in the middle of the cake comes out clean and the fruit is bubbling around the edges. Serve warm or at room temperature.