I recommend starting with this first as it needs to chill and firm up. In a medium saucepan, cook the butter over medium heat, stirring with a heatproof spatula, until the butter begins to foam and the milk solids turn brown. This can take up to 10 minutes, so be patient!
Scrape out all the butter and the brown bits into the bowl of your stand mixer (or another bowl if your mixer bowl is too big for the fridge!) and place in the fridge for at least 1 hour to firm up.
Preheat your oven to 350°F/180°C. Grease and line 2 8-inch cake pans.
In a jug, whisk together the eggs, egg yolks, vanilla, and buttermilk.
In a stand mixer with the paddle attachment, mix together the flour, sugar, baking powder, baking soda, cardamom and salt on a low speed until everything is combined. While the mixer is still running, add the butter a piece at a time. Your mixture should look like coarse sand
With the mixer still running, slowly pour in half of the wet ingredients. Increase the speed to medium for 30 seconds, then return to low. Add the rest of the wet ingredients while the mixture is still running. Increase the speed to medium again for 30 seconds. Use a spatula to fold the batter to make sure there are no flour pockets.
Divide the batter amongst the pans and then tap them against your counters to get rid of any air pockets. Bake for 18-22 minutes until golden brown. A toothpick inserted should come out clean
Take your butter out of the fridge. It should be firm, but when you press it with your finger it should leave an indent. In the stand mixer with a paddle attachment, beat together the butter and cream cheese on medium speed until it is completely smooth and fluffy.
In a bowl mix together the salt and powdered sugar. Add to the butter/cream cheese, half a cup at a time, mixing slowly after each addition.
Once all the sugar is incorporated, beat the frosting on medium until it is thick and very smooth, about 1-2 minutes. Add in the vanilla.
My recipes have been developed and tested in metric grams. I highly recommend using a weighing scale and measuring out your ingredients the metric way. I have provided a conversion to US cups but please note that I haven’t tested the recipe with this method. Just click on 'US Customary' above the ingredients. Butter: I use European style butter, like Kerry Gold, in my recipes. This will make your frosting much creamier and richer.Salt: If you don’t have kosher salt, halve the amount of salt called for in the recipe. 1 teaspoon kosher salt = ½ teaspoon fine saltButtermilk: No buttermilk on hand? Mix one tablespoon of lemon juice or white wine vinegar with 1 cup of milk, then let it sit for 5 minutes so it can curdle. Cream Cheese: Make sure your cream cheese is at room temperature before starting to make the frosting. If you are based in Europe, pat down your cream cheese with a paper towel, as cream cheese in Europe has more moisture. Storage: Cover the cake tightly and keep in the fridge for up to 5 days. Freezing: Freeze for up to 3 months, let the cake defrost overnight in the fridge and then come to room temperature when you’re ready to eat it.