Pre-heat the oven to 180C and line a 23 x 13 x 7cm loaf tin with parchment paper.
Combine flour, baking powder and salt. Sift and set aside.
Remove seeds from their pods. Discard pods. Crush seeds in a pestle and mortar. If you don't have a pestle and mortar, wrap the seeds in a newspaper and crush with a rolling pin (or the base of your frying pan). The seeds should not be crushed to a dust. The result should look like freshly cracked pepper. Set aside.
Cream butter and sugar till light and fluffy (my Kitchenaid Professional mixer is not optimal for creaming butter and sugar in small batches, many others feel the same way; I use a hand mixer). Add vanilla extract and sour cream and continue mixing till incorporated.
Add eggs one by one; mix well.
In batches, by hand (not using a hand mixer), gently fold in the flour, salt and baking powder mixture and cardamom seeds. Take care not to overmix the batter.
Transfer into lined loaf tin and place in the middle of the oven for 50-55 minutes or until a cake tester/skewer/toothpick inserted in the middle comes out clean.
Don't wait till the cake cools down, this is lovely when it is hot out of the oven. It will break and crumble a bit, but it is delicious.
