Preheat the oven to 180C/160C Fan and use the Wilton cake release to grease the inside of the bundt tin making sure that all areas of the inside of the tin are covered – leave to the side.
In a stand mixer, beat together the butter and sugar until light and fluffy.
Add in the flour, eggs, baking powder and lemon zest and beat again briefly until combined – try not to over beat!
Add half your blueberries to the mix, and fold through.
Pour into the prepared tin, and sprinkle the rest of the blueberries on top. (They'll sink when it bakes)
Bake for 50 minutes-60 minutes until baked through – check this by poking a skewer into the deepest part of the bundt.
Once baked, leave the cake to cool in the tin for 10 minutes, and then remove carefully and leave to cool fully on a wire rack.
For the Decoration
Whisk together the icing sugar and lemon juice and carefully drizzle onto the cake, and sprinkle over the fresh blueberries.
Notes
You can coat your blueberries in a tablespoon of flour/cornflour if you want to help prevent them sinking - but this isn't a guarantee.
Some blueberries will just sink straight to the bottom, but it'll be the top when it's turned out, so it won't matter!
This cake will last for 3 days once made!
You can use frozen blueberries if you wish, but be prepared for the cake to take longer to bake!
If you don't have the wilton cake release to use, you can butter and flour the tin.
If you cake gets stuck and won't come out, it wasn't greased enough.