Place a steamer basket in a wide pan, fill with water to just below the bottom of the basket. Add the chopped squash, cover and cook over a medium heat for approx. 20 mins. until very soft. Puree the squash until smooth, stir in the tangerine zest and juice, sugar, ginger and spices.
Candied pumpkin seeds
Bring the water and sugar to the boil in a pan, reduce to a syrupy consistency. Add the pumpkin seeds and fennel seeds, reduce over a medium heat, stirring constantly until the sugar becomes dry and sticks to the seeds. Remove the pan from the hob, continue to stir for about another 2 mins., transfer to a sheet of baking paper, leave to cool.
Bring the oat drink, oat flakes and salt to the boil in a pan, simmer over a medium heat for approx. 10 mins., stirring occasionally. Stir in the squash puree. Plate up the porridge, serve with the candied seeds.