Wash the sweet potatoes. Roast the sweet potatoes; this can be done in the microwave in a bowl covered with microwave-safe film for 7 minutes at 750 watts (do this in 2 batches).

Or in the oven at 200 degrees for 45 minutes.

Meanwhile, make the guacamole by mashing all the ingredients in a bowl.

Preheat the oven to 220 degrees.

Slice the potatoes, but not all the way through.

Fill them with the guacamole, corn, black beans, and sliced spring onions.

Sprinkle with cheese and place in the oven for 5 minutes until the cheese has melted.