Peel the sweet potato and cut into roughly 2 cm cubes. Soak the potato pieces in water for over 10 minutes and drain.

Add the potatoes, with enough water to cover them, to a pan. Cover with a lid and boil until they are soft enough to mash easily.

Once boiled, turn off the heat and drain the water. Use a masher to mash the potato.

Add the condensed milk, egg yolk (leaving 1 teaspoon of yolk) and rum to the potato and mix well. Preheat the oven to 180°C.

Roll the mixture from step 4 into a rough square about 1 cm thick on a sheet of baking paper or cling film

Spread the blueberry jam leaving a border of approx. 1 cm around the outside of the sweet potato mix. Leave 3 cm jam-free at the top edge.

Using the wrap or cling film, roll the mixture in the direction away from you.

Cut the roll into 6 pieces, place them with the cut side facing up and glaze them with the leftover egg yolk. Place them in aluminium cups and then into a muffin tray or pudding cups, etc.

Bake for approx. 20 minutes at 180°C. Once done, let them cool and take them out of the muffin tray in their aluminium cups.

If you don't plan on eating them right away, wrap them individually in cling film and store them in the refrigerator.