Put the frozen fruit, butter and sugar in a large bowl.
Heat in the microwave for 1-2 minutes until the butter has melted enough to stir through. It’s fine if the fruit is still mostly frozen.
Spoon the fruit into the bottom of your pudding basin.
Make the sponge
Place the butter and sugar in a large mixing bowl and whisk until creamy.
Add the eggs one by one, whisking between each addition. This will help stop the batter from splitting.
Next, whisk in the milk and vanilla.
Finally, sift in the flour and fold together until smooth.
Spoon the batter into the pudding basin on top of the fruit and level off.
Microwave the pudding
Fit the lid onto the pudding basin.
Place the pudding basin in the microwave and cook on full power for 12 minutes.
Remove the lid carefully as there will be steam, then place a plate on top of the basin and invert so that the pudding is on the plate and the basin can be lifted away.
Serve on its own, with cool cream or with hot custard.