Preheat your oven to 350°F (175°C) and line an 8-inch cake pan with parchment paper.
In a large mixing bowl, whisk together the sifted flour, sugar, baking powder, ground cardamom, and salt until well combined.
In another bowl, whisk the eggs, then add melted butter, vanilla extract, and mix until smooth and fragrant.
Pour the wet mixture into the dry ingredients and fold gently with a spatula until just combined, creating a thick batter.
Fold the diced apples into the batter, distributing them evenly throughout the mixture.
Pour the batter into the prepared cake pan, spreading it evenly with a spatula to fill all corners.
Bake in the preheated oven for about 45 minutes, or until the top is golden and a toothpick inserted into the center comes out clean.
Remove the cake from the oven and let it cool in the pan for 10 minutes before transferring to a wire rack to cool completely.
Once cooled, slice and serve the cake with a dusting of powdered sugar or a dollop of whipped cream if desired.
