Pre heat the e oven to 350°F. Lightly butter a 9×2-inch round cake pan. Line the bottom with a parchment circle cut to fit the pan and lightly flour the sides, tapping out the excess.
In a medium bowl, whisk the flour, ground ginger, cardamom, baking powder, baking soda, and salt. In a stand mixer fitted with the paddle attachment /with a hand mixer. Beat the butter and sugar on medium-high until well blended and fluffy, about 3 minutes. Add the eggs, one at a time, beating on medium speed until just blended and adding the vanilla with the second egg. Using a wide rubber spatula, fold in half the dry ingredients, then the sour cream, and then the remaining dry ingredients. Scrape the batter into the prepared pan and spread evenly. Bake for 15 minutes.
Meanwhile, make the topping: combine the sliced fruit in a small bowl. Add ginger, sugar and flour. Using a table fork, mix the ingredients to coat the fruit evenly. After the cake has baked for 15 minutes, scatter the topping evenly over the cake, working quickly. Continue baking until a toothpick inserted in the center of the cake comes out clean, another 35 minutes.
Serve warm or at room temperature, with whipped cream if you like.