Pre-heat the oven to 160C(320F) fan-forced and grease a 12 hole muffin tin. I used a silicone pan and didn’t need to grease it.
In the bowl of a food processor, give the berries a quick whiz to chop them up then scrape them out and set aside.
In the same food processor (no need to clean the bowl), blitz the almonds, butter, sugar, flour, eggs and vanilla until well combined (scrape down the sides a couple of times to make sure there are no dry ingredients stuck.
Add the berries back in and give it a quick whiz just until they are marbled through the batter.
Divide the batter between the muffin holes.
Sprinkle the slivered almonds on top and bake for 30-40 minutes or until a cake tester inserted in the middle of one comes out clean.
Transfer to a wire rack to cool completely and then dust with icing sugar before serving.