Preheat oven to 170 degrees celsius (fan-forced). Grease and line a 20cm square baking tin with baking paper and set aside.
Place the butter and chocolate into the Thermomix bowl. Melt for 3-4 minutes, 50 degrees, Speed 2. Allow to cool slightly.
Add the eggs, sugar and vanilla extract and mix for 10 seconds, Speed 4.
Add the flour and salt and mix for 10 seconds, Speed 4. Scrape down the sides of the bowl and mix for a further 5 seconds. Pour into the prepared tin.
Slice the Cadbury Creme Eggs in half lengthways (see tips) and arrange them on the top of your brownies (gooey side up). Only slightly press them into the brownie batter as they will sink whilst baking
Bake for 30 minutes or until the brownies are pale brown and flakey on top, but still dark and slightly gooey on the inside.
Once the brownies are cooled, slice into small pieces.