Preheat oven to 350 degrees. Grease the bundt pan well, using a pastry brush to get into all of the corners and edges. Dust in some flour and then tip the pan upside down to get rid of any excess flour.
In the bowl of a stand mixer cream the butter and the sugar. Add the zests and incorporate them into the butter, beat them on high for about 30 seconds to release the oils in the zest.
Add eggs one at a time, taking care to make sure each one is fully incorporated before adding the next.
Add almond extract and mix to combine.
Mix all of the dry ingredients together in a medium bowl.
Mix the buttermilk and the sour cream together.
Add in a bit of the dries to the bowl in the stand mixer, alternating with the sour cream mixture and finishing the batter with an addition of flour mix. Mix until just combined.
Pour in and level the batter and bake for about an hour, until a cake tester comes out clean.
Allow the cake to rest in the pan for 20 minutes or so, until the pan is just warm. If you flip the cake out too quickly it will be too fragile and may break.
Top with powdered sugar or icing and fresh fruit as desired.
Tip #1: Spoon and level flour to ensure an even bake.
Tip #2: Use a pastry brush to grease your pan to get into every nook and cranny.
Tip #3: Don't be tempted to flip your cake out too quickly.