Begin by preparing the rhubarb filling. Place the chopped rhubarb and sugar into a saucepan and cook over medium heat until the rhubarb is soft and releasing juices (about 5–7 minutes). Stir in the cornflour and cook for another 1–2 minutes until thickened. Let it cool completely.

To make the dough, mix flour, yeast, salt, and sugar in a large bowl. Add the warm milk, melted butter, and vanilla. Stir to form a soft dough.

Knead the dough for 10 minutes until smooth and elastic. Place in a greased bowl, cover, and let it rise in a warm spot for 1–2 hours, until doubled in size.

For the frangipane, cream together butter and sugar until light and fluffy. Stir in ground almonds, flour, almond extract, and milk. Set aside.

Once the dough has risen, turn it out onto a lightly floured surface and roll it into a large rectangle.

Spread the frangipane evenly over the dough, then spoon over the cooled rhubarb mixture.

Roll the dough up from the long side into a log. Slice into 9–12 pieces and place into a greased or lined baking tin.

Cover and let rise again for 30–45 minutes until puffy.

Preheat the oven to 180°C (350°F). Bake the buns for 25–30 minutes or until golden and cooked through.

Once cool, drizzle with icing sugar glaze and serve.