Preheat your oven 180 degrees celsius (fan-forced) and line the base of a 20cm round cake tin. Grease the sides.
Place the softened butter, caster sugar and vanilla extract into your Thermomix bowl and mix for 45 seconds, speed 3. Scrape down the sides of the bowl and mix for a further 14 seconds, speed 4 or until pale and creamy.
Turn the Thermomix onto speed 4 and remove the measuring cup. Add the eggs one at a time, leaving 5 seconds of mixing between each egg. Turn off your Thermomix.
Add the self raising and plain flour and mix for 12 seconds, speed 5 to combine. Scrape down the sides of the bowl and mix for a further 8 seconds, speed 5.
Transfer the mixture to your prepared cake tin and gently smooth the surface. Place the cake into your preheated oven and bake for 50 mins - 1 hour or until cooked when tested with a skewer.
Carefully remove the cake from the oven and allow it to cool for 10 minutes before transferring to a wire rack to cool completely.
The time it takes to cream the butter and sugar will depend on the temperature of the butter - if it's still quite cold it will take longer.
You can also use a loaf tin for this recipe, the cooking time will vary.
Your cake will develop a golden crust, this is normal.