Preheat over to 350F degrees. Grease a 9-inch springform pan (or cake pan). Place on a rimmed and parchment lined baking sheet to catch any leaks.
In a medium bowl, combine the flour, baking powder, cinnamon, salt, and cardamom.
In the bowl of a stand mixer or using an electric hand mixer, cream together the butter and sugar until light and fluffy, about 3 minutes. Beat in the egg and vanilla until incorporated. Beat in the sour cream. On low speed, add the flour mixture to the wet ingredients until combined.
Transfer the batter to prepared pan. (Don't forget to place on a rimmed baking sheet if using a springform pan!) Top the cake in a pretty design with peaches. Sprinkle the top with a spoonful of sugar to finish.
Bake for 45-60 minutes. I know, I know. Depending on the juiciness of the fruit you use and the ripeness, it could take up to 1 hour and 10 minutes. Start checking around the 35 minute mark though because it could bake quickly. Test with a toothpick inserted in the middle. It's ready when deeply golden and a toothpick comes out clean. If the sides are browning too quickly, place a piece of foil over the top after the 45 minute mark.
Remove from oven and carefully run a knife along the edges of the pan (and remove the outside clip if using the springform pan). Allow to cool on a wire rack. When ready to serve, sprinkle with powdered sugar and serve with whipped cream and an extra dusting of cinnamon.