Line the base and sides of a 28 x 18cm slice tin with baking paper and preheat your oven to 180 degrees.
Place the butter, sugar, flour and baking powder into your Thermomix bowl and blitz for 10 seconds on speed 7.
Scrape down the sides of your bowl and add the egg yolk and blitz for 7 seconds on speed 4 or until a soft dough forms.
Press the dough into the base of the prepared slice tin. Use two metal spoons to help spread the mixture across the surface.
Place the tray into the oven and bake for approximately 13 - 15 minutes or until the base has turned golden brown.
Allow the base to cool for 10 minutes before adding the raspberry jam.
To make the topping, place the caster sugar, egg and coconut into your Thermomix bowl and mix on speed two for 10 seconds or until combined.
Sprinkle the topping over the raspberry jam and bake the slice for a further 25 minutes or until the topping turns a lovely golden brown colour.
Remove the slice from the oven and let it cool in the tin before carefully transferring to your bench top to cut into pieces.